BACKGROUND: Pneumonia is common in adults hospitalized with laboratory-confirmed influenza, but the association between timeliness of influenza antiviral treatment and severe clinical outcomes in patients with influenza-associated pneumonia is not well characterized. METHODS: We included adults aged ≥18 years hospitalized with laboratory-confirmed influenza and a discharge diagnosis of pneumonia over 7 influenza seasons (2012-2019) sampled from a multistate population-based surveillance network. We evaluated 3 treatment groups based on timing of influenza antiviral initiation relative to admission date (day 0, day 1, days 2-5). Baseline characteristics and clinical outcomes were compared across groups using unweighted counts and weighted percentages accounting for the complex survey design. Logistic regression models were generated to evaluate the association between delayed treatment and 30-day all-cause mortality. RESULTS: A total of 26 233 adults were sampled in the analysis. Median age was 71 years and most (92.2%) had ≥1 non-immunocompromising condition. Overall, 60.9% started antiviral treatment on day 0, 29.5% on day 1, and 9.7% on days 2-5 (median, 2 days). Baseline characteristics were similar across groups. Thirty-day mortality occurred in 7.5%, 8.5%, and 10.2% of patients who started treatment on day 0, day 1, and days 2-5, respectively. Compared to those treated on day 0, adjusted odds ratio for death was 1.14 (95% confidence interval [CI], 1.01-1.27) in those starting treatment on day 1 and 1.40 (95% CI, 1.17-1.66) in those starting on days 2-5. CONCLUSIONS: Delayed initiation of antiviral treatment in patients hospitalized with influenza-associated pneumonia was associated with higher risk of death, highlighting the importance of timely initiation of antiviral treatment at admission.

IMPORTANCE: Seasonal influenza is associated with substantial disease burden. The relationship between census tract-based social vulnerability and clinical outcomes among patients with influenza remains unknown. OBJECTIVE: To characterize associations between social vulnerability and outcomes among patients hospitalized with influenza and to evaluate seasonal influenza vaccine and influenza antiviral utilization patterns across levels of social vulnerability. DESIGN, SETTING, AND PARTICIPANTS: This retrospective repeated cross-sectional study was conducted among adults with laboratory-confirmed influenza-associated hospitalizations from the 2014 to 2015 through the 2018 to 2019 influenza seasons. Data were from a population-based surveillance network of counties within 13 states. Data analysis was conducted in December 2023. EXPOSURE: Census tract-based social vulnerability. MAIN OUTCOMES AND MEASURES: Associations between census tract-based social vulnerability and influenza outcomes (intensive care unit admission, invasive mechanical ventilation and/or extracorporeal membrane oxygenation support, and 30-day mortality) were estimated using modified Poisson regression as adjusted prevalence ratios. Seasonal influenza vaccine and influenza antiviral utilization were also characterized across levels of social vulnerability. RESULTS: Among 57 964 sampled cases, the median (IQR) age was 71 (58-82) years; 55.5% (95% CI, 51.5%-56.0%) were female; 5.2% (5.0%-5.4%) were Asian or Pacific Islander, 18.3% (95% CI, 18.0%-18.6%) were Black or African American, and 64.6% (95% CI, 64.2%-65.0%) were White; and 6.6% (95% CI, 6.4%-68%) were Hispanic or Latino and 74.7% (95% CI, 74.3%-75.0%) were non-Hispanic or Latino. High social vulnerability was associated with higher prevalence of invasive mechanical ventilation and/or extracorporeal membrane oxygenation support (931 of 13 563 unweighted cases; adjusted prevalence ratio [aPR], 1.25 [95% CI, 1.13-1.39]), primarily due to socioeconomic status (790 of 11 255; aPR, 1.31 [95% CI, 1.17-1.47]) and household composition and disability (773 of 11 256; aPR, 1.20 [95% CI, 1.09-1.32]). Vaccination status, presence of underlying medical conditions, and respiratory symptoms partially mediated all significant associations. As social vulnerability increased, the proportion of patients receiving seasonal influenza vaccination declined (-19.4% relative change across quartiles; P < .001) as did the proportion vaccinated by October 31 (-6.8%; P < .001). No differences based on social vulnerability were found in in-hospital antiviral receipt, but early in-hospital antiviral initiation (-1.0%; P = .01) and prehospital antiviral receipt (-17.3%; P < .001) declined as social vulnerability increased. CONCLUSIONS AND RELEVANCE: In this cross-sectional study, social vulnerability was associated with a modestly increased prevalence of invasive mechanical ventilation and/or extracorporeal membrane oxygenation support among patients hospitalized with influenza. Contributing factors may have included worsened baseline respiratory health and reduced receipt of influenza prevention and prehospital or early in-hospital treatment interventions among persons residing in low socioeconomic areas.

Annually, tens of thousands of U.S. children and adolescents are hospitalized with seasonal influenza virus infection. Both influenza vaccination and early initiation of antiviral treatment can reduce complications of influenza. Using data from two U.S. influenza surveillance networks for children and adolescents aged <18 years with medically attended, laboratory-confirmed influenza for whom antiviral treatment is recommended, the percentage who received treatment was calculated. Trends in antiviral treatment of children and adolescents hospitalized with influenza from the 2017-18 to the 2023-2024 influenza seasons were also examined. Since 2017-18, when 70%-86% of hospitalized children and adolescents with influenza received antiviral treatment, the proportion receiving treatment notably declined. Among children and adolescents with influenza during the 2023-24 season, 52%-59% of those hospitalized received antiviral treatment. During the 2023-24 season, 31% of those at higher risk for influenza complications seen in the outpatient setting in one network were prescribed antiviral treatment. These findings demonstrate that influenza antiviral treatment is underutilized among children and adolescents who could benefit from treatment. All hospitalized children and adolescents, and those at higher risk for influenza complications in the outpatient setting, should receive antiviral treatment as soon as possible for suspected or confirmed influenza.

BACKGROUND: While the estimated number of U.S. influenza-associated deaths is reported annually, detailed data on the epidemiology of influenza-associated deaths, including the burden of in-hospital versus post-hospital discharge deaths are limited. METHODS: Using data from the 2010-11 through 2018-19 seasons from the Influenza Hospitalization Surveillance Network, we linked cases to death certificates to identify patients who died from any cause during their influenza hospital stay or within 30 days post discharge. We described demographic and clinical characteristics of patients who died in hospital versus post discharge and characterized locations and causes of death (COD). RESULTS: Among 121,390 cases hospitalized with laboratory-confirmed influenza over 9 seasons, 5.5% died; 76% of deaths were in patients ≥65 years, 71% were non-Hispanic White, and 34% had ≥4 underlying medical conditions. Among all patients with an influenza-associated hospitalization who died, 48% of deaths occurred after hospital discharge; the median days from discharge to death was 9 days (IQR 3-19 days). Post-discharge deaths more often occurred in older patients and among those with underlying medical conditions. Only 37% of patients who died had "influenza" as a COD on their death certificate. Influenza was more frequently listed as a COD among persons who died in-hospital compared with cardiovascular disease among those who died after discharge. CONCLUSIONS: All-cause mortality burden is substantial among patients hospitalized with influenza, with almost 50% of deaths occurring within 30 days after hospital discharge. Surveillance systems should consider capture of post-discharge outcomes to better characterize the impact of influenza on all-cause mortality.

PROBLEM/CONDITION: Seasonal influenza accounts for 9.3 million-41 million illnesses, 100,000-710,000 hospitalizations, and 4,900-51,000 deaths annually in the United States. Since 2003, the Influenza Hospitalization Surveillance Network (FluSurv-NET) has been conducting population-based surveillance for laboratory-confirmed influenza-associated hospitalizations in the United States, including weekly rate estimations and descriptions of clinical characteristics and outcomes for hospitalized patients. However, a comprehensive summary of trends in hospitalization rates and clinical data collected from the surveillance platform has not been available. REPORTING PERIOD: 2010-11 through 2022-23 influenza seasons. DESCRIPTION OF SYSTEM: FluSurv-NET conducts population-based surveillance for laboratory-confirmed influenza-associated hospitalizations among children and adults. During the reporting period, the surveillance network included 13-16 participating sites each influenza season, with prespecified geographic catchment areas that covered 27 million-29 million persons and included an estimated 8.8%-9.5% of the U.S. population. A case was defined as a person residing in the catchment area within one of the participating states who had a positive influenza laboratory test result within 14 days before or at any time during their hospitalization. Each site abstracted case data from hospital medical records into a standardized case report form, with selected variables submitted to CDC on a weekly basis for rate estimations. Weekly and cumulative laboratory-confirmed influenza-associated hospitalization rates per 100,000 population were calculated for each season from 2010-11 through 2022-23 and stratified by patient age (0-4 years, 5-17 years, 18-49 years, 50-64 years, and ≥65 years), sex, race and ethnicity, influenza type, and influenza A subtype. During the 2020-21 season, only the overall influenza hospitalization rate was reported because case counts were insufficient to estimate stratified rates. RESULTS: During the 2010-11 to 2022-23 influenza seasons, laboratory-confirmed influenza-associated hospitalization rates varied significantly across seasons. Before the COVID-19 pandemic, hospitalization rates per 100,000 population ranged from 8.7 (2011-12) to 102.9 (2017-18) and had consistent seasonality. After SARS-CoV-2 emerged, the hospitalization rate for 2020-21 was 0.8, and the rate did not return to recent prepandemic levels until 2022-23. Inconsistent seasonality also was observed during 2020-21 through 2022-23, with influenza activity being very low during 2020-21, extending later than usual during 2021-22, and occurring early during 2022-23. Molecular assays, particularly multiplex standard molecular assays, were the most common influenza test type in recent seasons, increasing from 12% during 2017-18 for both pediatric and adult cases to 43% and 55% during 2022-23 for pediatric and adult cases, respectively. During each season, adults aged ≥65 years consistently had the highest influenza-associated hospitalization rate across all age groups, followed in most seasons by children aged 0-4 years. Black or African American and American Indian or Alaska Native persons had the highest age-adjusted influenza-associated hospitalization rates across these seasons. Among patients hospitalized with influenza, the prevalence of at least one underlying medical condition increased with increasing age, ranging from 36.9% among children aged 0-4 years to 95.4% among adults aged ≥65 years. Consistently across each season, the most common underlying medical conditions among children and adolescents were asthma, neurologic disorders, and obesity. The most common underlying medical conditions among adults were hypertension, obesity, chronic metabolic disease, chronic lung disease, and cardiovascular disease. The proportion of FluSurv-NET patients with acute respiratory signs and symptoms at hospital admission decreased from 90.6% during 2018-19 to 83.2% during 2022-23. Although influenza antiviral use increased during the 2010-11 through the 2017-18 influenza seasons, it decreased from 90.2% during 2018-19 to 79.1% during 2022-23, particularly among children and adolescents. Admission to the intensive care unit, need for invasive mechanical ventilation, and in-hospital death ranged from 14.1% to 22.3%, 4.9% to 11.1%, and 2.2% to 3.5% of patients hospitalized with influenza, respectively, during the reported surveillance period. INTERPRETATIONS: Influenza continues to cause severe morbidity and mortality, particularly in older adults, and disparities have persisted in racial and ethnic minority groups. Persons with underlying medical conditions represented a large proportion of patients hospitalized with influenza. Increased use of multiplex tests and other potential changes in facility-level influenza testing practices (e.g., influenza screening at all hospital admissions) could have implications for the detection of influenza infections among hospitalized patients. Antiviral use decreased in recent seasons, and explanations for the decrease should be further evaluated. PUBLIC HEALTH ACTION: Continued robust influenza surveillance is critical to monitor progress in efforts to encourage antiviral treatment and improve clinical outcomes for persons hospitalized with influenza. In addition, robust influenza surveillance can potentially reduce disparities by informing efforts to increase access to preventive measures for influenza and monitoring any subsequent changes in hospitalization rates.

Severe outcomes were common among adults hospitalized for COVID-19 or influenza, while the percentage of COVID-19 hospitalizations involving critical care decreased from October 2021 to September 2022. During the Omicron BA.5 period, intensive care unit admission frequency was similar for COVID-19 and influenza, although patients with COVID-19 had a higher frequency of in-hospital death.

BACKGROUND: Older age and chronic conditions are associated with severe influenza outcomes; however, data are only comprehensively available for adults ≥65 years old. Using data from the Influenza Hospitalization Surveillance Network (FluSurv-NET), we identified characteristics associated with severe outcomes in adults 18-49 years old hospitalized with influenza. METHODS: We included FluSurv-NET data from nonpregnant adults 18-49 years old hospitalized with laboratory-confirmed influenza during the 2011-2012 through 2018-2019 seasons. We used bivariate and multivariable logistic regression to determine associations between select characteristics and severe outcomes including intensive care unit (ICU) admission, invasive mechanical ventilation (IMV), and in-hospital death. RESULTS: A total of 16 140 patients aged 18-49 years and hospitalized with influenza were included in the analysis; the median age was 39 years, and 26% received current-season influenza vaccine before hospitalization. Obesity, asthma, and diabetes mellitus were the most common chronic conditions. Conditions associated with a significantly increased risk of severe outcomes included age group 30-39 or 40-49 years (IMV, age group 30-39 years: adjusted odds ratio [aOR], 1.25; IMV, age group 40-49 years: aOR, 1.36; death, age group 30-39 years: aOR, 1.28; death, age group 40-49 years: aOR, 1.69), being unvaccinated (ICU: aOR, 1.18; IMV: aOR, 1.25; death: aOR, 1.48), and having chronic conditions including extreme obesity and chronic lung, cardiovascular, metabolic, neurologic, or liver diseases (ICU: range aOR, 1.22-1.56; IMV: range aOR, 1.17-1.54; death: range aOR, 1.43-2.36). CONCLUSIONS: To reduce the morbidity and mortality associated with influenza among adults aged 18-49 years, health care providers should strongly encourage receipt of annual influenza vaccine and lifestyle/behavioral modifications, particularly among those with chronic medical conditions.

BACKGROUND: Influenza is a substantial cause of annual morbidity and mortality; however, correctly identifying those patients at increased risk for severe disease is often challenging. Several severity indices have been developed; however, these scores have not been validated for use in patients with influenza. We evaluated the discrimination of three clinical disease severity scores in predicting severe influenza-associated outcomes. METHODS: We used data from the Influenza Hospitalization Surveillance Network to assess outcomes of patients hospitalized with influenza in the United States during the 2017-2018 influenza season. We computed patient scores at admission for three widely used disease severity scores: CURB-65, Quick Sepsis-Related Organ Failure Assessment (qSOFA), and the Pneumonia Severity Index (PSI). We then grouped patients with severe outcomes into four severity tiers, ranging from ICU admission to death, and calculated receiver operating characteristic (ROC) curves for each severity index in predicting these tiers of severe outcomes. RESULTS: Among 8252 patients included in this study, we found that all tested severity scores had higher discrimination for more severe outcomes, including death, and poorer discrimination for less severe outcomes, such as ICU admission. We observed the highest discrimination for PSI against in-hospital mortality, at 0.78. CONCLUSIONS: We observed low to moderate discrimination of all three scores in predicting severe outcomes among adults hospitalized with influenza. Given the substantial annual burden of influenza disease in the United States, identifying a prediction index for severe outcomes in adults requiring hospitalization with influenza would be beneficial for patient triage and clinical decision-making.

During the 2022-23 influenza season, early increases in influenza activity, co-circulation of influenza with other respiratory viruses, and high influenza-associated hospitalization rates, particularly among children and adolescents, were observed. This report describes the 2022-23 influenza season among children and adolescents aged <18 years, including the seasonal severity assessment; estimates of U.S. influenza-associated medical visits, hospitalizations, and deaths; and characteristics of influenza-associated hospitalizations. The 2022-23 influenza season had high severity among children and adolescents compared with thresholds based on previous seasons' influenza-associated outpatient visits, hospitalization rates, and deaths. Nationally, the incidences of influenza-associated outpatient visits and hospitalization for the 2022-23 season were similar for children aged <5 years and higher for children and adolescents aged 5-17 years compared with previous seasons. Peak influenza-associated outpatient and hospitalization activity occurred in late November and early December. Among children and adolescents hospitalized with influenza during the 2022-23 season in hospitals participating in the Influenza Hospitalization Surveillance Network, a lower proportion were vaccinated (18.3%) compared with previous seasons (35.8%-41.8%). Early influenza circulation, before many children and adolescents had been vaccinated, might have contributed to the high hospitalization rates during the 2022-23 season. Among symptomatic hospitalized patients, receipt of influenza antiviral treatment (64.9%) was lower than during pre-COVID-19 pandemic seasons (80.8%-87.1%). CDC recommends that all persons aged ≥6 months without contraindications should receive the annual influenza vaccine, ideally by the end of October.

BACKGROUND: Influenza burden varies across seasons, partly due to differences in circulating influenza virus types or subtypes. Using data from the US population-based surveillance system, Influenza Hospitalization Surveillance Network (FluSurv-NET), we aimed to assess the severity of influenza-associated outcomes in individuals hospitalised with laboratory-confirmed influenza virus infections during the 2010-11 to 2018-19 influenza seasons. METHODS: To evaluate the association between influenza virus type or subtype causing the infection (influenza A H3N2, A H1N1pdm09, and B viruses) and in-hospital severity outcomes (intensive care unit [ICU] admission, use of mechanical ventilation or extracorporeal membrane oxygenation [ECMO], and death), we used FluSurv-NET to capture data for laboratory-confirmed influenza-associated hospitalisations from the 2010-11 to 2018-19 influenza seasons for individuals of all ages living in select counties in 13 US states. All individuals had to have an influenza virus test within 14 days before or during their hospital stay and an admission date between Oct 1 and April 30 of an influenza season. Exclusion criteria were individuals who did not have a complete chart review; cases from sites that contributed data for three or fewer seasons; hospital-onset cases; cases with unidentified influenza type; cases of multiple influenza virus type or subtype co-infection; or individuals younger than 6 months and ineligible for the influenza vaccine. Logistic regression models adjusted for influenza season, influenza vaccination status, age, and FluSurv-NET site compared odds of in-hospital severity by virus type or subtype. When missing, influenza A subtypes were imputed using chained equations of known subtypes by season. FINDINGS: Data for 122 941 individuals hospitalised with influenza were captured in FluSurv-NET from the 2010-11 to 2018-19 seasons; after exclusions were applied, 107 941 individuals remained and underwent influenza A virus imputation when missing A subtype (43·4%). After imputation, data for 104 969 remained and were included in the final analytic sample. Averaging across imputed datasets, 57·7% (weighted percentage) had influenza A H3N2, 24·6% had influenza A H1N1pdm09, and 17·7% had influenza B virus infections; 16·7% required ICU admission, 6·5% received mechanical ventilation or ECMO, and 3·0% died (95% CIs had a range of less than 0·1% and are not displayed). Individuals with A H1N1pdm09 had higher odds of in-hospital severe outcomes than those with A H3N2: adjusted odds ratios (ORs) for A H1N1pdm09 versus A H3N2 were 1·42 (95% CI 1·32-1·52) for ICU admission; 1·79 (1·60-2·00) for mechanical ventilation or ECMO use; and 1·25 (1·07-1·46) for death. The adjusted ORs for individuals infected with influenza B versus influenza A H3N2 were 1·06 (95% CI 1·01-1·12) for ICU admission, 1·14 (1·05-1·24) for mechanical ventilation or ECMO use, and 1·18 (1·07-1·31) for death. INTERPRETATION: Despite a higher burden of hospitalisations with influenza A H3N2, we found an increased likelihood of in-hospital severe outcomes in individuals hospitalised with influenza A H1N1pdm09 or influenza B virus. Thus, it is important for individuals to receive an annual influenza vaccine and for health-care providers to provide early antiviral treatment for patients with suspected influenza who are at increased risk of severe outcomes, not only when there is high influenza A H3N2 virus circulation but also when influenza A H1N1pdm09 and influenza B viruses are circulating. FUNDING: The US Centers for Disease Control and Prevention.

Background The COVID-19 pandemic has caused substantial morbidity and mortality.Objectives To describe monthly demographic and clinical trends among adults hospitalized with COVID-19.Design Pooled cross-sectional.Setting 99 counties within 14 states participating in the Coronavirus Disease 2019-Associated Hospitalization Surveillance Network (COVID-NET).Patients U.S. adults (aged ≥18 years) hospitalized with laboratory-confirmed COVID-19 during March 1-December 31, 2020.Measurements Monthly trends in weighted percentages of interventions and outcomes including length of stay (LOS), intensive care unit admissions (ICU), invasive mechanical ventilation (IMV), vasopressor use and in-hospital death (death). Monthly hospitalization, ICU and death rates per 100,000 population.Results Among 116,743 hospitalized adults, median age was 62 years. Among 18,508 sampled adults, median LOS decreased from 6.4 (March) to 4.6 days (December). Remdesivir and systemic corticosteroid use increased from 1.7% and 18.9% (March) to 53.8% and 74.2% (December), respectively. Frequency of ICU decreased from 37.8% (March) to 20.5% (December). IMV (27.8% to 8.7%), vasopressors (22.7% to 8.8%) and deaths (13.9% to 8.7%) decreased from March to October; however, percentages of these interventions and outcomes remained stable or increased in November and December. Percentage of deaths significantly decreased over time for non-Hispanic White patients (p-value &lt;0.01) but not non-Hispanic Black or Hispanic patients. Rates of hospitalization (105.3 per 100,000), ICU (20.2) and death (11.7) were highest during December.Limitations COVID-NET covers approximately 10% of the U.S. population; findings may not be generalizable to the entire country.Conclusions After initial improvement during April-October 2020, trends in interventions and outcomes worsened during November-December, corresponding with the 3rd peak of the U.S. pandemic. These data provide a longitudinal assessment of trends in COVID-19-associated outcomes prior to widespread COVID-19 vaccine implementation.Competing Interest StatementDr. Evan Anderson reports grants from Pfizer, grants from Merck, grants from PaxVax, grants from Micron, grants from Sanofi-Pasteur, grants from Janssen, grants from MedImmune, grants from GSK, personal fees from Sanofi-Pasteur, personal fees from Pfizer, personal fees from Medscape, personal fees from Kentucky Bioprocessing, Inc, personal fees from Sanofi-Pasteur, outside the submitted work. Dr. William Schaffner reports personal fees from VBI Vaccines, outside the submitted work. Funding StatementThis work was supported by the Centers of Disease Control and Prevention through an Emerging Infections Program cooperative agreement (grant CK17-1701) and through a Council of State and Territorial Epidemiologists cooperative agreement (grant NU38OT000297-02-00).Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:This activity was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy. Sites participating in COVID-NET obtained approval from their respective state and local Institutional Review Boards, as applicable.All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting check ist(s) and other pertinent material as supplementary files, if applicable.YesPublicly available data referred to in this analysis can be found at: https://gis.cdc.gov/grasp/covidnet/covid19_3.html https://gis.cdc.gov/grasp/covidnet/covid19_3.html

Background As of May 15, 2020, the United States has reported the greatest number of coronavirus disease 2019 (COVID-19) cases and deaths globally.Objective To describe risk factors for severe outcomes among adults hospitalized with COVID-19.Design Cohort study of patients identified through the Coronavirus Disease 2019-Associated Hospitalization Surveillance Network.Setting 154 acute care hospitals in 74 counties in 13 states.Patients 2491 patients hospitalized with laboratory-confirmed COVID-19 during March 1-May 2, 2020.Measurements Age, sex, race/ethnicity, and underlying medical conditions.Results Ninety-two percent of patients had ≥1 underlying condition; 32% required intensive care unit (ICU) admission; 19% invasive mechanical ventilation; 15% vasopressors; and 17% died during hospitalization. Independent factors associated with ICU admission included ages 50-64, 65-74, 75-84 and ≥85 years versus 18-39 years (adjusted risk ratio (aRR) 1.53, 1.65, 1.84 and 1.43, respectively); male sex (aRR 1.34); obesity (aRR 1.31); immunosuppression (aRR 1.29); and diabetes (aRR 1.13). Independent factors associated with in-hospital mortality included ages 50-64, 65-74, 75-84 and ≥85 years versus 18-39 years (aRR 3.11, 5.77, 7.67 and 10.98, respectively); male sex (aRR 1.30); immunosuppression (aRR 1.39); renal disease (aRR 1.33); chronic lung disease (aRR 1.31); cardiovascular disease (aRR 1.28); neurologic disorders (aRR 1.25); and diabetes (aRR 1.19). Race/ethnicity was not associated with either ICU admission or death.Limitation Data were limited to patients who were discharged or died in-hospital and had complete chart abstractions; patients who were still hospitalized or did not have accessible medical records were excluded.Conclusion In-hospital mortality for COVID-19 increased markedly with increasing age. These data help to characterize persons at highest risk for severe COVID-19-associated outcomes and define target groups for prevention and treatment strategies.Funding Source This work was supported by grant CK17-1701 from the Centers of Disease Control and Prevention through an Emerging Infections Program cooperative agreement and by Cooperative Agreement Number NU38OT000297-02-00 awarded to the Council of State and Territorial Epidemiologists from the Centers for Disease Control and Prevention.Competing Interest StatementH. Keipp Talbot reports personal fees from Seqirus outside the submitted work. William Schaffner reports personal fees from Pfizer and personal fees from Roche Diagnostics outside the submitted work. Evan Anderson reports personal fees from Abbvie and Pfizer outside the submitted work. H. Keipp Talbot reports grants from Sanofi outside the submitted work; Mary Hill reports grants from CSTE, during the conduct of the study; Melissa Sutton reports grants from CDC Emerging Infections Program during the conduct of the study; William Schaffner reports grants from CDC during the conduct of the study. Sue Kim reports grants from CSTE during the conduct of the study. Evan Anderson reports grants from Pfizer, grants from MedImmune, grants from Regeneron, grants from PaxVax, grants from Merck, grants from Novavax, grants from Sanofi-Pasteur, grants from Micron, outside the submitted work. Laurie Billing reports grants from the Council of State and Territorial Epidemiologists (CSTE) and the Centers for Disease Control and Prevention (CDC) during the conduct of the study.Funding StatementThis work was supported by grant CK17-1701 from the Centers of Disease Control and Prevention through an Emerging Infections Program cooperative agreement and by Cooperative Agreement Number NU38OT000297-02-00 awarded to the Council of State and Territorial Epidemiologists from the Centers for Disease Control and Prevention.Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesAll necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that al clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesAggregate data is available on CDC’s COVID-NET Interactive website. https://gis.cdc.gov/grasp/COVIDNet/COVID19_3.html https://gis.cdc.gov/grasp/COVIDNet/COVID19_5.html

Background There is uncertainty about the burden of hospitalization associated with RSV and influenza in children, including those with underlying medical conditions.Methods We applied previously developed methodology (Goldstein et al., Epidemiology 2012) to HealthCare Cost and Utilization Project (HCUP) hospitalization data and additional data related to asthma diagnosis/previous history in hospitalized children to estimate RSV and influenza-associated hospitalization rates in different subpopulations of US children between 2003-2010.Results The estimated average annual rates (per 100,000 children) of RSV-associated hospitalization with a respiratory cause (ICD-9 codes 460-519) present anywhere in the discharge diagnosis were 2381 (95% CI(2252,2515)) in age &lt;1y; 710.6(609.1,809.2) (age 1y); 395(327.7,462.4) (age 2y); 211.3(154.6,266.8) (age 3y); 111.1(62.4,160.1) (age 4y); 72.3(29.3,116.4) (ages 5-6y); 35.6(9.9,62.2) (ages 7-11y); and 39(17.5,60.6) (ages 12-17y).The corresponding rates of influenza-associated hospitalization were lower, ranging from 181(142.5,220.3) in age &lt;1y to 17.9(11.7,24.2) in ages 12-17y. The relative risks for RSV-related hospitalization associated with a prior diagnosis of asthma in age groups under 5y ranged between 3.1(2.1,4.7) (age &lt;1y) to 6.7(4.2,11.8) (age 2y); the corresponding risks for influenza-related hospitalization ranged from 2.8(2.1,4) (age &lt;1y) to 4.9(3.8,6.4) (age 3y).Conclusions RSV-associated hospitalization rates in young children are high and decline rapidly with age. Young children with an asthma diagnosis should be target groups for RSV and influenza-related mitigation efforts, possibly including RSV prophylaxis for the youngest children.

Introduction: As most public health decisions are made at the local level, public health interventions implemented at the local level may vary by their own unique circumstances, such as demographic composition or the availability of resources. Our objective is to estimate and characterize county-level flu vaccine uptakes among Medicare-covered adults aged 65 years. Methods: The flu vaccine uptake was estimated from Medicare Fee-for-Service claims for those who continuously enrolled during the 20182019 flu season. County-level characteristics were obtained from Centers for Disease Control and Prevention (CDC)s Minority Health Social Vulnerability Index and Behavioral Risk Factor Surveillance System data as well as Health Resources and Services Administration's Area Health Resources File. A generalized linear regression was used to assess the relationship between selected characteristics and uptake. Results: A total of 30,265,047 beneficiaries from 3,125 counties were identified, of which 53% received a flu vaccination during the 20182019 flu season. For 3,006 counties with more than 500 Medicare beneficiaries, the mean county-level uptake was estimated to be 47.7%. The mean uptakes in counties designated as a health professional shortage area (HPSA) (42.6% and 48.4%, respectively), were lower than the uptakes for the non-HPSA counties (53.8%). Metro counties (53.2%) showed higher uptakes than non-metro counties (44.2%). Regression analysis results showed that the percent of working adults aged 1864 years and female were positively associated, while the percent of Black and Hispanic adults were negatively associated. Proportions of persons with limited proficiency of English, college education or above, single parent families, multi-unit housing, and living in group quarters were positively associated and significant. Conclusions: The results confirmed that county-level flu vaccine uptakes are low, reflect persistent racial disparities in vaccine uptake, and that Medicare populations in medically underserved communities with lower socioeconomic status need more attention in improving flu vaccine uptake. 2023

Introduction: As most public health decisions are made at the local level, public health interventions implemented at the local level may vary by their own unique circumstances, such as demographic composition or the availability of resources. Our objective is to estimate and characterize county-level flu vaccine uptakes among Medicare-covered adults aged ≥65 years. Methods: The flu vaccine uptake was estimated from Medicare Fee-for-Service claims for those who continuously enrolled during the 2018–2019 flu season. County-level characteristics were obtained from Centers for Disease Control and Prevention (CDC)’s Minority Health Social Vulnerability Index and Behavioral Risk Factor Surveillance System data as well as Health Resources and Services Administration's Area Health Resources File. A generalized linear regression was used to assess the relationship between selected characteristics and uptake. Results: A total of 30,265,047 beneficiaries from 3,125 counties were identified, of which 53% received a flu vaccination during the 2018–2019 flu season. For 3,006 counties with more than 500 Medicare beneficiaries, the mean county-level uptake was estimated to be 47.7%. The mean uptakes in counties designated as a health professional shortage area (HPSA) (42.6% and 48.4%, respectively), were lower than the uptakes for the non-HPSA counties (53.8%). Metro counties (53.2%) showed higher uptakes than non-metro counties (44.2%). Regression analysis results showed that the percent of working adults aged 18–64 years and female were positively associated, while the percent of Black and Hispanic adults were negatively associated. Proportions of persons with limited proficiency of English, college education or above, single parent families, multi-unit housing, and living in group quarters were positively associated and significant. Conclusions: The results confirmed that county-level flu vaccine uptakes are low, reflect persistent racial disparities in vaccine uptake, and that Medicare populations in medically underserved communities with lower socioeconomic status need more attention in improving flu vaccine uptake. © 2023

From surveillance data of patients hospitalized with laboratory-confirmed influenza in the United States during the 2015-2016 through 2018-2019 seasons, initiation of antiviral treatment increased from 86% to 94%, with increases seen across all age groups. However, 62% started therapy ≥3 days after illness onset, driven by late presentation to care.

BACKGROUND: The COVID-19-Associated Hospitalization Surveillance Network (COVID-NET) required a sampling methodology that allowed for production of timely population-based clinical estimates to inform the ongoing US COVID-19 pandemic response. METHODS: We developed a flexible sampling approach that considered reporting delays, differential hospitalized case burden across surveillance sites, and changing geographic and demographic trends over time. We incorporated weighting methods to adjust for the probability of selection and non-response, and to calibrate the sampled case distribution to the population distribution on demographics. We additionally developed procedures for variance estimation. RESULTS: Between March 2020 and June 2021, 19,293 (10.4%) of all adult hospitalized cases were sampled for chart abstraction. Variance estimates for select variables of interest were within desired ranges. CONCLUSIONS: COVID-NET's sampling methodology allowed for reporting of robust and timely, population-based data on the clinical epidemiology of COVID-19-associated hospitalizations and evolving trends over time, while attempting to reduce data collection burden on surveillance sites. Such methods may provide a general framework for other surveillance systems needing to quickly and efficiently collect and disseminate data for public health action.

The 2022-23 influenza season shows an early rise in pediatric influenza-associated hospitalizations (1). SARS-CoV-2 viruses also continue to circulate (2). The current influenza season is the first with substantial co-circulation of influenza viruses and SARS-CoV-2 (3). Although both seasonal influenza viruses and SARS-CoV-2 can contribute to substantial pediatric morbidity (3-5), whether coinfection increases disease severity compared with that associated with infection with one virus alone is unknown. This report describes characteristics and prevalence of laboratory-confirmed influenza virus and SARS-CoV-2 coinfections among patients aged <18 years who had been hospitalized or died with influenza as reported to three CDC surveillance platforms during the 2021-22 influenza season. Data from two Respiratory Virus Hospitalizations Surveillance Network (RESP-NET) platforms (October 1, 2021-April 30, 2022),(§) and notifiable pediatric deaths associated(¶) with influenza virus and SARS-CoV-2 coinfection (October 3, 2021-October 1, 2022)** were analyzed. SARS-CoV-2 coinfections occurred in 6% (32 of 575) of pediatric influenza-associated hospitalizations and in 16% (seven of 44) of pediatric influenza-associated deaths. Compared with patients without coinfection, a higher proportion of those hospitalized with coinfection received invasive mechanical ventilation (4% versus 13%; p = 0.03) and bilevel positive airway pressure or continuous positive airway pressure (BiPAP/CPAP) (6% versus 16%; p = 0.05). Among seven coinfected patients who died, none had completed influenza vaccination, and only one received influenza antivirals.(††) To help prevent severe outcomes, clinicians should follow recommended respiratory virus testing algorithms to guide treatment decisions and consider early antiviral treatment initiation for pediatric patients with suspected or confirmed influenza, including those with SARS-CoV-2 coinfection who are hospitalized or at increased risk for severe illness. The public and parents should adopt prevention strategies including considering wearing well-fitted, high-quality masks when respiratory virus circulation is high and staying up-to-date with recommended influenza and COVID-19 vaccinations for persons aged ≥6 months.

INTRODUCTION: CDC estimates that influenza resulted in 9-41 million illnesses, 140,000-710,000 hospitalizations, and 12,000-52,000 deaths annually during 2010-2020. Persons from some racial and ethnic minority groups have historically experienced higher rates of severe influenza and had lower influenza vaccination coverage compared with non-Hispanic White (White) persons. This report examines influenza hospitalization and vaccination rates by race and ethnicity during a 12-13-year period (through the 2021-22 influenza season). METHODS: Data from population-based surveillance for laboratory-confirmed influenza-associated hospitalizations in selected states participating in the Influenza-Associated Hospitalization Surveillance Network (FluSurv-NET) from the 2009-10 through 2021-22 influenza seasons (excluding 2020-21) and influenza vaccination coverage data from the Behavioral Risk Factor Surveillance System (BRFSS) from the 2010-11 through 2021-22 influenza seasons were analyzed by race and ethnicity. RESULTS: From 2009-10 through 2021-22, age-adjusted influenza hospitalization rates (hospitalizations per 100,000 population) were higher among non-Hispanic Black (Black) (rate ratio [RR] = 1.8), American Indian or Alaska Native (AI/AN; RR = 1.3), and Hispanic (RR = 1.2) adults, compared with the rate among White adults. During the 2021-22 season, influenza vaccination coverage was lower among Hispanic (37.9%), AI/AN (40.9%), Black (42.0%), and other/multiple race (42.6%) adults compared with that among White (53.9%) and non-Hispanic Asian (Asian) (54.2%) adults; coverage has been consistently higher among White and Asian adults compared with that among Black and Hispanic adults since the 2010-11 season. The disparity in vaccination coverage by race and ethnicity was present among those who reported having medical insurance, a personal health care provider, and a routine medical checkup in the past year. CONCLUSIONS AND IMPLICATIONS FOR PUBLIC HEALTH PRACTICE: Racial and ethnic disparities in influenza disease severity and influenza vaccination coverage persist. Health care providers should assess patient vaccination status at all medical visits and offer (or provide a referral for) all recommended vaccines. Tailored programmatic efforts to provide influenza vaccination through nontraditional settings, along with national and community-level efforts to improve awareness of the importance of influenza vaccination in preventing illness, hospitalization, and death among racial and ethnic minority communities might help address health care access barriers and improve vaccine confidence, leading to decreases in disparities in influenza vaccination coverage and disease severity.

BACKGROUND: Influenza is a persistent public health problem associated with severe morbidity and mortality. Drug use is related to myriad health complications, but the relationship between drug use and severe influenza outcomes is not well understood. The study objective was to evaluate the relationship between drug use and severe influenza-associated outcomes. METHODS: Data were collected by the Influenza Hospitalization Surveillance Network (FluSurv-NET) from the 2016-2017 through 2018-2019 influenza seasons. Among persons hospitalized with influenza, descriptive statistics and logistic regression models were used to analyze differences in demographic characteristics, risk and behavioral factors, and severe outcomes (intensive care unit [ICU] admission, mechanical ventilation, or death) between people who use drugs (PWUD), defined as having documented drug use within the past year, and non-PWUD. RESULTS: Among 48,430 eligible hospitalized influenza cases, 2019 were PWUD and 46,411 were non-PWUD. PWUD were younger than non-PWUD and more likely to be male, non-Hispanic Black or Hispanic/Latino, smoke tobacco, abuse alcohol, and have chronic conditions including asthma, chronic liver disease, chronic lung disease, or immunosuppressive conditions. PWUD had greater odds of ICU admission and mechanical ventilation, but not death compared with non-PWUD; however, these findings were not statistically significant after adjustment. Opioid use specifically was associated with increased risk of ICU admission and mechanical ventilation. CONCLUSION: These results support targeted initiatives to prevent influenza in this population, including influenza vaccination, which remains one of the most important tools to prevent influenza infection and associated severe outcomes.

Before the emergence of SARS-CoV-2, the virus that causes COVID-19, influenza activity in the United States typically began to increase in the fall and peaked in February. During the 2021-22 season, influenza activity began to increase in November and remained elevated until mid-June, featuring two distinct waves, with A(H3N2) viruses predominating for the entire season. This report summarizes influenza activity during October 3, 2021-June 11, 2022, in the United States and describes the composition of the Northern Hemisphere 2022-23 influenza vaccine. Although influenza activity is decreasing and circulation during summer is typically low, remaining vigilant for influenza infections, performing testing for seasonal influenza viruses, and monitoring for novel influenza A virus infections are important. An outbreak of highly pathogenic avian influenza A(H5N1) is ongoing; health care providers and persons with exposure to sick or infected birds should remain vigilant for onset of symptoms consistent with influenza. Receiving a seasonal influenza vaccine each year remains the best way to protect against seasonal influenza and its potentially severe consequences.

Listeriosis is a serious infection usually caused by eating food contaminated with the bacterium Listeria monocytogenes. An estimated 1,600 persons become ill with listeriosis each year, among whom approximately 260 die. Persons at higher risk for listeriosis include pregnant persons and their newborns, adults aged ≥65 years, and persons with weakened immune systems. Persons with invasive listeriosis usually report symptoms starting 1-4 weeks after eating food contaminated with L. monocytogenes; however, some persons who become infected have reported symptoms starting as late as 70 days after exposure or as early as the same day of exposure (1). On January 29, 2021, PulseNet, the national molecular subtyping surveillance network coordinated by CDC, identified a multistate cluster of three L. monocytogenes infections: two from Maryland and one from Connecticut (2). CDC, the Food and Drug Administration (FDA), and state and local partners began an investigation on February 1, 2021. A total of 13 outbreak-related cases were eventually identified from four states. All patients reported Hispanic ethnicity; 12 patients were hospitalized, and one died. Rapid food testing and record collection by regulatory agencies enabled investigators to identify a brand of queso fresco made with pasteurized milk as the likely source of the outbreak, leading to an initial product recall on February 19, 2021. Fresh, soft Hispanic-style cheeses made with pasteurized milk are a well-documented source of listeriosis outbreaks. These cheeses can be contaminated with L. monocytogenes unless stringent hygienic controls are implemented, and the processing environment is monitored for contamination (3). U.S. public health agencies should establish or improve communications, including new methods of disseminating information that also effectively reach Hispanic populations, to emphasize the risk from eating fresh, soft Hispanic-style cheeses, even those made with pasteurized milk.

BACKGROUND: Influenza virus and SARS-CoV-2 are significant causes of respiratory illness in children. METHODS: Influenza and COVID-19-associated hospitalizations among children <18 years old were analyzed from FluSurv-NET and COVID-NET, two population-based surveillance systems with similar catchment areas and methodology. The annual COVID-19-associated hospitalization rate per 100 000 during the ongoing COVID-19 pandemic (October 1, 2020-September 30, 2021) was compared to influenza-associated hospitalization rates during the 2017-18 through 2019-20 influenza seasons. In-hospital outcomes, including intensive care unit (ICU) admission and death, were compared. RESULTS: Among children <18 years old, the COVID-19-associated hospitalization rate (48.2) was higher than influenza-associated hospitalization rates: 2017-18 (33.5), 2018-19 (33.8), and 2019-20 (41.7). The COVID-19-associated hospitalization rate was higher among adolescents 12-17 years old (COVID-19: 59.9; influenza range: 12.2-14.1), but similar or lower among children 5-11 (COVID-19: 25.0; influenza range: 24.3-31.7) and 0-4 (COVID-19: 66.8; influenza range: 70.9-91.5) years old. Among children <18 years old, a higher proportion with COVID-19 required ICU admission compared with influenza (26.4% vs 21.6%; p<0.01). Pediatric deaths were uncommon during both COVID-19- and influenza-associated hospitalizations (0.7% vs 0.5%; p=0.28). CONCLUSIONS: In the setting of extensive mitigation measures during the COVID-19 pandemic, the annual COVID-19-associated hospitalization rate during 2020-2021 was higher among adolescents and similar or lower among children <12 years old compared with influenza during the three seasons before the COVID-19 pandemic. COVID-19 adds substantially to the existing burden of pediatric hospitalizations and severe outcomes caused by influenza and other respiratory viruses.

BACKGROUND: Pregnant women may be at increased risk for severe influenza-associated outcomes. OBJECTIVE: To describe characteristics and outcomes of hospitalized pregnant women with influenza. DESIGN: Repeated cross-sectional study. SETTING: The population-based U.S. Influenza Hospitalization Surveillance Network during the 2010-2011 through 2018-2019 influenza seasons. PATIENTS: Pregnant women (aged 15 to 44 years) hospitalized with laboratory-confirmed influenza identified through provider-initiated or facility-based testing practices. MEASUREMENTS: Clinical characteristics, interventions, and in-hospital maternal and fetal outcomes were obtained through medical chart abstraction. Multivariable logistic regression was used to evaluate the association between influenza A subtype and severe maternal influenza-associated outcomes, including intensive care unit (ICU) admission, mechanical ventilation, extracorporeal membrane oxygenation, or in-hospital death. RESULTS: Of 9652 women aged 15 to 44 years and hospitalized with influenza, 2690 (27.9%) were pregnant. Among the 2690 pregnant women, the median age was 28 years, 62% were in their third trimester, and 42% had at least 1 underlying condition. Overall, 32% were vaccinated against influenza and 88% received antiviral treatment. Five percent required ICU admission, 2% required mechanical ventilation, and 0.3% (n = 8) died. Pregnant women with influenza A H1N1 were more likely to have severe outcomes than those with influenza A H3N2 (adjusted risk ratio, 1.9 [95% CI, 1.3 to 2.8]). Most women (71%) were still pregnant at hospital discharge. Among 754 women who were no longer pregnant at discharge, 96% had a pregnancy resulting in live birth, and 3% experienced fetal loss. LIMITATION: Maternal and fetal outcomes that occurred after hospital discharge were not captured. CONCLUSION: Over 9 influenza seasons, one third of reproductive-aged women hospitalized with influenza were pregnant. Influenza A H1N1 was associated with more severe maternal outcomes. Pregnant women remain a high-priority target group for vaccination. PRIMARY FUNDING SOURCE: Centers for Disease Control and Prevention.

IMPORTANCE: Racial and ethnic minority groups are disproportionately affected by COVID-19. OBJECTIVES: To evaluate whether rates of severe COVID-19, defined as hospitalization, intensive care unit (ICU) admission, or in-hospital death, are higher among racial and ethnic minority groups compared with non-Hispanic White persons. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study included 99 counties within 14 US states participating in the COVID-19-Associated Hospitalization Surveillance Network. Participants were persons of all ages hospitalized with COVID-19 from March 1, 2020, to February 28, 2021. EXPOSURES: Laboratory-confirmed COVID-19-associated hospitalization, defined as a positive SARS-CoV-2 test within 14 days prior to or during hospitalization. MAIN OUTCOMES AND MEASURES: Cumulative age-adjusted rates (per 100 000 population) of hospitalization, ICU admission, and death by race and ethnicity. Rate ratios (RR) were calculated for each racial and ethnic group compared with White persons. RESULTS: Among 153 692 patients with COVID-19-associated hospitalizations, 143 342 (93.3%) with information on race and ethnicity were included in the analysis. Of these, 105 421 (73.5%) were 50 years or older, 72 159 (50.3%) were male, 28 762 (20.1%) were Hispanic or Latino, 2056 (1.4%) were non-Hispanic American Indian or Alaska Native, 7737 (5.4%) were non-Hispanic Asian or Pacific Islander, 40 806 (28.5%) were non-Hispanic Black, and 63 981 (44.6%) were White. Compared with White persons, American Indian or Alaska Native, Latino, Black, and Asian or Pacific Islander persons were more likely to have higher cumulative age-adjusted rates of hospitalization, ICU admission, and death as follows: American Indian or Alaska Native (hospitalization: RR, 3.70; 95% CI, 3.54-3.87; ICU admission: RR, 6.49; 95% CI, 6.01-7.01; death: RR, 7.19; 95% CI, 6.47-7.99); Latino (hospitalization: RR, 3.06; 95% CI, 3.01-3.10; ICU admission: RR, 4.20; 95% CI, 4.08-4.33; death: RR, 3.85; 95% CI, 3.68-4.01); Black (hospitalization: RR, 2.85; 95% CI, 2.81-2.89; ICU admission: RR, 3.17; 95% CI, 3.09-3.26; death: RR, 2.58; 95% CI, 2.48-2.69); and Asian or Pacific Islander (hospitalization: RR, 1.03; 95% CI, 1.01-1.06; ICU admission: RR, 1.91; 95% CI, 1.83-1.98; death: RR, 1.64; 95% CI, 1.55-1.74). CONCLUSIONS AND RELEVANCE: In this cross-sectional analysis, American Indian or Alaska Native, Latino, Black, and Asian or Pacific Islander persons were more likely than White persons to have a COVID-19-associated hospitalization, ICU admission, or in-hospital death during the first year of the US COVID-19 pandemic. Equitable access to COVID-19 preventive measures, including vaccination, is needed to minimize the gap in racial and ethnic disparities of severe COVID-19.

OBJECTIVE: To estimate population-based rates and to describe clinical characteristics of hospital-acquired (HA) influenza. DESIGN: Cross-sectional study. SETTING: US Influenza Hospitalization Surveillance Network (FluSurv-NET) during 2011-2012 through 2018-2019 seasons. METHODS: Patients were identified through provider-initiated or facility-based testing. HA influenza was defined as a positive influenza test date and respiratory symptom onset >3 days after admission. Patients with positive test date >3 days after admission but missing respiratory symptom onset date were classified as possible HA influenza. RESULTS: Among 94,158 influenza-associated hospitalizations, 353 (0.4%) had HA influenza. The overall adjusted rate of HA influenza was 0.4 per 100,000 persons. Among HA influenza cases, 50.7% were 65 years of age or older, and 52.0% of children and 95.7% of adults had underlying conditions; 44.9% overall had received influenza vaccine prior to hospitalization. Overall, 34.5% of HA cases received ICU care during hospitalization, 19.8% required mechanical ventilation, and 6.7% died. After including possible HA cases, prevalence among all influenza-associated hospitalizations increased to 1.3% and the adjusted rate increased to 1.5 per 100,000 persons. CONCLUSIONS: Over 8 seasons, rates of HA influenza were low but were likely underestimated because testing was not systematic. A high proportion of patients with HA influenza were unvaccinated and had severe outcomes. Annual influenza vaccination and implementation of robust hospital infection control measures may help to prevent HA influenza and its impacts on patient outcomes and the healthcare system.

OBJECTIVES: Some studies suggested more COVID-19-associated hospitalizations among racial and ethnic minorities. To inform public health practice, the COVID-19-associated Hospitalization Surveillance Network (COVID-NET) quantified associations between race/ethnicity, census tract socioeconomic indicators, and COVID-19-associated hospitalization rates. METHODS: Using data from COVID-NET population-based surveillance reported during March 1-April 30, 2020 along with socioeconomic and denominator data from the US Census Bureau, we calculated COVID-19-associated hospitalization rates by racial/ethnic and census tract-level socioeconomic strata. RESULTS: Among 16,000 COVID-19-associated hospitalizations, 34.8% occurred among non-Hispanic White (White) persons, 36.3% among non-Hispanic Black (Black) persons, and 18.2% among Hispanic or Latino (Hispanic) persons. Age-adjusted COVID-19-associated hospitalization rate were 151.6 (95% Confidence Interval (CI): 147.1-156.1) in census tracts with >15.2%-83.2% of persons living below the federal poverty level (high-poverty census tracts) and 75.5 (95% CI: 72.9-78.1) in census tracts with 0%-4.9% of persons living below the federal poverty level (low-poverty census tracts). Among White, Black, and Hispanic persons living in high-poverty census tracts, age-adjusted hospitalization rates were 120.3 (95% CI: 112.3-128.2), 252.2 (95% CI: 241.4-263.0), and 341.1 (95% CI: 317.3-365.0), respectively, compared with 58.2 (95% CI: 55.4-61.1), 304.0 (95%: 282.4-325.6), and 540.3 (95% CI: 477.0-603.6), respectively, in low-poverty census tracts. CONCLUSIONS: Overall, COVID-19-associated hospitalization rates were highest in high-poverty census tracts, but rates among Black and Hispanic persons were high regardless of poverty level. Public health practitioners must ensure mitigation measures and vaccination campaigns address needs of racial/ethnic minority groups and people living in high-poverty census tracts.

Although COVID-19-associated hospitalizations and deaths have occurred more frequently in adults,(†) COVID-19 can also lead to severe outcomes in children and adolescents (1,2). Schools are opening for in-person learning, and many prekindergarten children are returning to early care and education programs during a time when the number of COVID-19 cases caused by the highly transmissible B.1.617.2 (Delta) variant of SARS-CoV-2, the virus that causes COVID-19, is increasing.(§) Therefore, it is important to monitor indicators of severe COVID-19 among children and adolescents. This analysis uses Coronavirus Disease 2019-Associated Hospitalization Surveillance Network (COVID-NET)(¶) data to describe COVID-19-associated hospitalizations among U.S. children and adolescents aged 0-17 years. During March 1, 2020-August 14, 2021, the cumulative incidence of COVID-19-associated hospitalizations was 49.7 per 100,000 children and adolescents. The weekly COVID-19-associated hospitalization rate per 100,000 children and adolescents during the week ending August 14, 2021 (1.4) was nearly five times the rate during the week ending June 26, 2021 (0.3); among children aged 0-4 years, the weekly hospitalization rate during the week ending August 14, 2021, was nearly 10 times that during the week ending June 26, 2021.** During June 20-July 31, 2021, the hospitalization rate among unvaccinated adolescents (aged 12-17 years) was 10.1 times higher than that among fully vaccinated adolescents. Among all hospitalized children and adolescents with COVID-19, the proportions with indicators of severe disease (such as intensive care unit [ICU] admission) after the Delta variant became predominant (June 20-July 31, 2021) were similar to those earlier in the pandemic (March 1, 2020-June 19, 2021). Implementation of preventive measures to reduce transmission and severe outcomes in children is critical, including vaccination of eligible persons, universal mask wearing in schools, recommended mask wearing by persons aged ≥2 years in other indoor public spaces and child care centers,(††) and quarantining as recommended after exposure to persons with COVID-19.(§§).

IMPORTANCE: Racial and ethnic minority groups, such as Black, Hispanic, American Indian or Alaska Native, and Asian or Pacific Islander persons, often experience higher rates of severe influenza disease. OBJECTIVE: To describe rates of influenza-associated hospitalization, intensive care unit (ICU) admission, and in-hospital death by race and ethnicity over 10 influenza seasons. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used data from the Influenza-Associated Hospitalization Surveillance Network (FluSurv-NET), which conducts population-based surveillance for laboratory-confirmed influenza-associated hospitalizations in selected counties, representing approximately 9% of the US population. Influenza hospitalizations from the 2009 to 2010 season to the 2018 to 2019 season were analyzed. Data were analyzed from October 2020 to July 2021. MAIN OUTCOMES AND MEASURES: The main outcomes were age-adjusted and age-stratified rates of influenza-associated hospitalization, ICU admission, and in-hospital death by race and ethnicity overall and by influenza season. RESULTS: Among 113 352 persons with an influenza-associated hospitalization (34 436 persons [32.0%] aged ≥75 years; 61 009 [53.8%] women), 70 225 persons (62.3%) were non-Hispanic White (White), 24 850 persons (21.6%) were non-Hispanic Black (Black), 11 903 persons (10.3%) were Hispanic, 5517 persons (5.1%) were non-Hispanic Asian or Pacific Islander, and 857 persons (0.7%) were non-Hispanic American Indian or Alaska Native. Among persons aged younger than 75 years and compared with White persons of the same ages, Black persons were more likely to be hospitalized (eg, age 50-64 years: rate ratio [RR], 2.50 95% CI, 2.43-2.57) and to be admitted to an ICU (eg, age 50-64 years: RR, 2.09; 95% CI, 1.96-2.23). Among persons aged younger than 50 years and compared with White persons of the same ages, American Indian or Alaska Native persons were more likely to be hospitalized (eg, age 18-49 years: RR, 1.72; 95% CI, 1.51-1.96) and to be admitted to an ICU (eg, age 18-49 years: RR, 1.84; 95% CI, 1.40-2.42). Among children aged 4 years or younger and compared with White children, hospitalization rates were higher in Black children (RR, 2.21; 95% CI, 2.10-2.33), Hispanic children (RR, 1.87; 95% CI, 1.77-1.97), American Indian or Alaska Native children (RR, 3.00; 95% CI, 2.55-3.53), and Asian or Pacific Islander children (RR, 1.26; 95% CI, 1.16-1.38), as were rates of ICU admission (Black children: RR, 2.74; 95% CI, 2.43-3.09; Hispanic children: RR, 1.96; 95% CI, 1.73-2.23; American Indian and Alaska Native children: RR, 3.51; 95% CI, 2.45-5.05). In this age group and compared with White children, in-hospital death rates were higher among Hispanic children (RR, 2.98; 95% CI, 1.23-7.19), Black children (RR, 3.39; 95% CI, 1.40-8.18), and Asian or Pacific Islander children (RR, 4.35; 95% CI, 1.55-12.22). Few differences were observed in rates of severe influenza-associated outcomes by race and ethnicity among adults aged 75 years or older. For example, in this age group, compared with White adults, hospitalization rates were slightly higher only among Black adults (RR, 1.05; 95% CI 1.02-1.09). Overall, Black persons had the highest age-adjusted hospitalization rate (68.8 [95% CI, 68.0-69.7] hospitalizations per 100 000 population) and ICU admission rate (11.6 [95% CI, 11.2-11.9] admissions per 100 000 population). CONCLUSIONS AND RELEVANCE: This cross-sectional study found racial and ethnic disparities in rates of severe influenza-associated disease. These data identified subgroups for whom improvements in influenza prevention efforts could be targeted.

BACKGROUND: The COVID-19 pandemic has caused substantial morbidity and mortality. OBJECTIVE: To describe monthly clinical trends among adults hospitalized with COVID-19. DESIGN: Pooled cross-sectional study. SETTING: 99 counties in 14 states participating in the Coronavirus Disease 2019-Associated Hospitalization Surveillance Network (COVID-NET). PATIENTS: U.S. adults (aged ≥18 years) hospitalized with laboratory-confirmed COVID-19 during 1 March to 31 December 2020. MEASUREMENTS: Monthly hospitalizations, intensive care unit (ICU) admissions, and in-hospital death rates per 100 000 persons in the population; monthly trends in weighted percentages of interventions, including ICU admission, mechanical ventilation, and vasopressor use, among an age- and site-stratified random sample of hospitalized case patients. RESULTS: Among 116 743 hospitalized adults with COVID-19, the median age was 62 years, 50.7% were male, and 40.8% were non-Hispanic White. Monthly rates of hospitalization (105.3 per 100 000 persons), ICU admission (20.2 per 100 000 persons), and death (11.7 per 100 000 persons) peaked during December 2020. Rates of all 3 outcomes were highest among adults aged 65 years or older, males, and Hispanic or non-Hispanic Black persons. Among 18 508 sampled hospitalized adults, use of remdesivir and systemic corticosteroids increased from 1.7% and 18.9%, respectively, in March to 53.8% and 74.2%, respectively, in December. Frequency of ICU admission, mechanical ventilation, and vasopressor use decreased from March (37.8%, 27.8%, and 22.7%, respectively) to December (20.5%, 12.3%, and 12.8%, respectively); use of noninvasive respiratory support increased from March to December. LIMITATION: COVID-NET covers approximately 10% of the U.S. population; findings may not be generalizable to the entire country. CONCLUSION: Rates of COVID-19-associated hospitalization, ICU admission, and death were highest in December 2020, corresponding with the third peak of the U.S. pandemic. The frequency of intensive interventions for management of hospitalized patients decreased over time. These data provide a longitudinal assessment of clinical trends among adults hospitalized with COVID-19 before widespread implementation of COVID-19 vaccines. PRIMARY FUNDING SOURCE: Centers for Disease Control and Prevention.