Last data update: Jan 27, 2025. (Total: 48650 publications since 2009)
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Social vulnerability, intervention utilization, and outcomes in US adults hospitalized with influenza
Adams K , Yousey-Hindes K , Bozio CH , Jain S , Kirley PD , Armistead I , Alden NB , Openo KP , Witt LS , Monroe ML , Kim S , Falkowski A , Lynfield R , McMahon M , Hoffman MR , Shaw YP , Spina NL , Rowe A , Felsen CB , Licherdell E , Lung K , Shiltz E , Thomas A , Talbot HK , Schaffner W , Crossland MT , Olsen KP , Chang LW , Cummings CN , Tenforde MW , Garg S , Hadler JL , O'Halloran A . JAMA Netw Open 2024 7 (11) e2448003 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. |
Laboratory-confirmed influenza-associated hospitalizations among children and adults - Influenza Hospitalization Surveillance Network, United States, 2010-2023
Naquin A , O'Halloran A , Ujamaa D , Sundaresan D , Masalovich S , Cummings CN , Noah K , Jain S , Kirley PD , Alden NB , Austin E , Meek J , Yousey-Hindes K , Openo K , Witt L , Monroe ML , Henderson J , Nunez VT , Lynfield R , McMahon M , Shaw YP , McCahon C , Spina N , Engesser K , Tesini BL , Gaitan MA , Shiltz E , Lung K , Sutton M , Hendrick MA , Schaffner W , Talbot HK , George A , Zahid H , Reed C , Garg S , Bozio CH . MMWR Surveill Summ 2024 73 (6) 1-18 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. |
Performance of established disease severity scores in predicting severe outcomes among adults hospitalized with influenza-FluSurv-NET, 2017-2018
Doyle JD , Garg S , O'Halloran AC , Grant L , Anderson EJ , Openo KP , Alden NB , Herlihy R , Meek J , Yousey-Hindes K , Monroe ML , Kim S , Lynfield R , McMahon M , Muse A , Spina N , Irizarry L , Torres S , Bennett NM , Gaitan MA , Hill M , Cummings CN , Reed C , Schaffner W , Talbot HK , Self WH , Williams D . Influenza Other Respir Viruses 2023 17 (12) e13228 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. |
Influenza antiviral use in patients hospitalized with laboratory-confirmed influenza in the United States, FluSurv-NET, 2015-2019
Tenforde MW , Cummings CN , O'Halloran AC , Rothrock G , Kirley PD , Alden NB , Meek J , Yousey-Hindes K , Openo KP , Anderson EJ , Monroe ML , Kim S , Nunez VT , McMahon M , McMullen C , Khanlian SA , Spina NL , Muse A , Gaitán MA , Felsen CB , Lung K , Shiltz E , Sutton M , Thomas A , Talbot HK , Schaffner W , Price A , Chatelain R , Reed C , Garg S . Open Forum Infect Dis 2023 10 (1) ofac681 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. |
Influenza Activity and Composition of the 2022-23 Influenza Vaccine - United States, 2021-22 Season.
Merced-Morales A , Daly P , Abd Elal AI , Ajayi N , Annan E , Budd A , Barnes J , Colon A , Cummings CN , Iuliano AD , DaSilva J , Dempster N , Garg S , Gubareva L , Hawkins D , Howa A , Huang S , Kirby M , Kniss K , Kondor R , Liddell J , Moon S , Nguyen HT , O'Halloran A , Smith C , Stark T , Tastad K , Ujamaa D , Wentworth DE , Fry AM , Dugan VG , Brammer L . MMWR Morb Mortal Wkly Rep 2022 71 (29) 913-919 ![]() ![]() 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. |
Epidemiology, clinical characteristics, and outcomes of influenza-associated hospitalizations in U.S. children over 9 seasons following the 2009 H1N1 pandemic
Kamidani S , Garg S , Rolfes MA , Campbell AP , Cummings CN , Haston JC , Openo KP , Fawcett E , Chai SJ , Herlihy R , Yousey-Hindes K , Monroe ML , Kim S , Lynfield R , Smelser C , Muse A , Felsen CB , Billing L , Thomas A , Talbot HK , Schaffner W , Risk I , Anderson EJ . Clin Infect Dis 2022 75 (11) 1930-1939 BACKGROUND: Recent population-based data are limited regarding influenza-associated hospitalizations in U.S. children. METHODS: We identified children <18 years hospitalized with laboratory-confirmed influenza during 2010-2019 seasons through CDC's Influenza Hospitalization Surveillance Network. Adjusted hospitalization and in-hospital mortality rates were calculated, and multivariable logistic regression was conducted to evaluate risk factors for pneumonia, intensive care unit (ICU) admission, mechanical ventilation, and death. RESULTS: Over 9 seasons, adjusted influenza-associated hospitalization incidence rates ranged from 10-375 per 100,000 persons each season and were highest among infants <6 months. Rates decreased with increasing age. The highest in-hospital mortality rates were observed in children <6 months (0.73 per 100,000 persons). Over time, antiviral treatment significantly increased from 56% to 85% (P < .001) and influenza vaccination rates increased from 33% to 44% (P = .003). Among the 13,235 hospitalized children, 2,676 (20%) of hospitalized children were admitted to the ICU, 2,262 (17%) had pneumonia, 690 (5%) required mechanical ventilation, and 72 (0.5%) died during hospitalization. As compared with those <6 months of age, hospitalized children ≥13 years had higher odds of pneumonia (adjusted odds ratios [aOR], 2.7; 95% confidence interval [CI], 2.1-3.4), ICU admission (aOR, 1.6; 95% CI, 1.3-1.9), mechanical ventilation (aOR, 1.6; 95% CI, 1.1-2.2), and death (aOR, 3.3; 95% CI, 1.2-9.3). CONCLUSIONS: Hospitalization and death rates were greatest in younger children at the population level. Among hospitalized children, however, older children had a higher risk of severe outcomes. Continued efforts to prevent and attenuate influenza in children are needed. |
Hospital-acquired influenza in the United States, FluSurv-NET, 2011-2012 through 2018-2019
Cummings CN , O'Halloran AC , Azenkot T , Reingold A , Alden NB , Meek JI , Anderson EJ , Ryan PA , Kim S , McMahon M , McMullen C , Spina NL , Bennett NM , Billing LM , Thomas A , Schaffner W , Talbot HK , George A , Reed C , Garg S . Infect Control Hosp Epidemiol 2021 43 (10) 1-7 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. |
Spatial and temporal clustering of patients hospitalized with laboratory-confirmed influenza in the United States
Sloan C , Chandrasekhar R , Mitchel E , Ndi D , Miller L , Thomas A , Bennett NM , Chai S , Spencer M , Eckel S , Spina N , Monroe M , Anderson EJ , Lynfield R , Yousey-Hindes K , Bargsten M , Zansky S , Lung K , Schroeder M , Cummings CN , Garg S , Schaffner W , Lindegren ML . Epidemics 2020 31 100387 BACKGROUND: Timing of influenza spread across the United States is dependent on factors including local and national travel patterns and climate. Local epidemic intensity may be influenced by social, economic and demographic patterns. Data are needed to better explain how local socioeconomic factors influence both the timing and intensity of influenza seasons to result in national patterns. METHODS: To determine the spatial and temporal impacts of socioeconomics on influenza hospitalization burden and timing, we used population-based laboratory-confirmed influenza hospitalization surveillance data from the CDC-sponsored Influenza Hospitalization Surveillance Network (FluSurv-NET) at up to 14 sites from the 2009/2010 through 2013/2014 seasons (n = 35,493 hospitalizations). We used a spatial scan statistic and spatiotemporal wavelet analysis, to compare temporal patterns of influenza spread between counties and across the country. RESULTS: There were 56 spatial clusters identified in the unadjusted scan statistic analysis using data from the 2010/2011 through the 2013/2014 seasons, with relative risks (RRs) ranging from 0.09 to 4.20. After adjustment for socioeconomic factors, there were five clusters identified with RRs ranging from 0.21 to 1.20. In the wavelet analysis, most sites were in phase synchrony with one another for most years, except for the H1N1 pandemic year (2009-2010), wherein most sites had differential epidemic timing from the referent site in Georgia. CONCLUSIONS: Socioeconomic factors strongly impact local influenza hospitalization burden. Influenza phase synchrony varies by year and by socioeconomics, but is less influenced by socioeconomics than is disease burden. |
Noncountable tuberculosis case reporting, National Tuberculosis Surveillance System, United States, 2010-2014
Pratt RH , Manangan LP , Cummings CN , Langer AJ . Public Health Rep 2019 135 (1) 33354919884302 OBJECTIVES: Supplemental federal funding is allocated to state and local tuberculosis (TB) programs using a formula that considers only countable cases reported to the National Tuberculosis Surveillance System (NTSS). Health departments submit reports of cases, which are countable unless another (US or international) jurisdiction has already counted the case or the case represents a recurrence of TB diagnosed </=12 months after completion of treatment for a previous TB episode. Noncountable cases are a resource burden, so in 2009, NTSS began accepting noncountable case reports as an indicator of program burden. We sought to describe the volume and completeness of noncountable case reports. METHODS: We analyzed 2010-2014 NTSS data to determine the number and distribution of noncountable cases reported. We also surveyed jurisdictions to determine the completeness of noncountable case reporting and obtain information on jurisdictions' experience in reporting noncountable cases. In addition, we prepared a hypothetical recalculation of the funding formula to evaluate the effect of including noncountable cases on funding allocations. RESULTS: Of 54 067 TB case reports analyzed, 1720 (3.2%) were noncountable; 47 of 60 (78.3%) jurisdictions reported >/=1 noncountable case. Of 60 programs surveyed, 34 (56.7%) responded. Of the 34 programs that responded, 24 (70.6%) had not reported all their noncountable cases to NTSS, and 11 (32.4%) stated that reporting noncountable cases was overly burdensome, considering the cases were not funded. CONCLUSIONS: Complete data on noncountable TB cases help support estimates of programmatic burden. Ongoing training and a streamlined reporting system to NTSS can facilitate noncountable case reporting. |
Age-related differences in hospitalization rates, clinical presentation, and outcomes among older adults hospitalized with influenza - U.S. Influenza Hospitalization Surveillance Network (FluSurv-NET)
Czaja CA , Miller L , Alden N , Wald HL , Cummings CN , Rolfes MA , Anderson EJ , Bennett NM , Billing LM , Chai SJ , Eckel S , Mansmann R , McMahon M , Monroe ML , Muse A , Risk I , Schaffner W , Thomas AR , Yousey-Hindes K , Garg S , Herlihy RK . Open Forum Infect Dis 2019 6 (7) BACKGROUND: Rates of influenza hospitalizations differ by age, but few data are available regarding differences in laboratory-confirmed rates among adults aged >/=65 years. METHODS: We evaluated age-related differences in influenza-associated hospitalization rates, clinical presentation, and outcomes among 19 760 older adults with laboratory-confirmed influenza at 14 FluSurv-NET sites during the 2011-2012 through 2014-2015 influenza seasons using 10-year age groups. RESULTS: There were large stepwise increases in the population rates of influenza hospitalization with each 10-year increase in age. Rates ranged from 101-417, 209-1264, and 562-2651 per 100 000 persons over 4 influenza seasons in patients aged 65-74 years, 75-84 years, and >/=85 years, respectively. Hospitalization rates among adults aged 75-84 years and >/=85 years were 1.4-3.0 and 2.2-6.4 times greater, respectively, than rates for adults aged 65-74 years. Among patients hospitalized with laboratory-confirmed influenza, there were age-related differences in demographics, medical histories, and symptoms and signs at presentation. Compared to hospitalized patients aged 65-74 years, patients aged >/=85 years had higher odds of pneumonia (aOR, 1.2; 95% CI, 1.0-1.3; P = .01) and in-hospital death or transfer to hospice (aOR, 2.1; 95% CI, 1.7-2.6; P < .01). CONCLUSIONS: Age-related differences in the incidence and severity of influenza hospitalizations among adults aged >/=65 years can inform prevention and treatment efforts, and data should be analyzed and reported using additional age strata. |
Outcomes of immunocompromised adults hospitalized with laboratory-confirmed influenza in the United States, 2011-2015
Collins JP , Campbell AP , Openo K , Farley MM , Cummings CN , Hill M , Schaffner W , Lindegren ML , Thomas A , Billing L , Bennett N , Spina N , Bargsten M , Lynfield R , Eckel S , Ryan P , Yousey-Hindes K , Herlihy R , Kirley PD , Garg S , Anderson EJ . Clin Infect Dis 2019 70 (10) 2121-2130 BACKGROUND: Hospitalized immunocompromised (IC) adults with influenza may have worse outcomes than hospitalized non-immunocompromised adults. METHODS: We identified adults (>/=18 years) hospitalized with laboratory-confirmed influenza during 2011-2015 seasons through CDC's Influenza Hospitalization Surveillance Network. IC patients had >/=1: HIV/AIDS, cancer, stem cell or organ transplantation, non-steroid immunosuppressive therapy, immunoglobulin deficiency, asplenia, or other rare conditions. We compared demographic and clinical characteristics of IC and non-IC adults using descriptive statistics and used multivariable logistic regression and Cox proportional hazards models to control for confounding by patient demographic characteristics, pre-existing medical conditions, influenza vaccination, and other factors. RESULTS: Among 35,348 adults, 3633 (10%) were IC; cancer (44%), non-steroid immunosuppressive therapy (44%), and HIV (17%) were most common. IC patients were more likely than non-IC patients to have received influenza vaccination (53% vs. 46%; p<0.001), and ~85% of both groups received antivirals. In multivariable analysis, IC adults had higher mortality (adjusted odds ratio (aOR) [95% confidence interval (CI)]: 1.46 [1.20-1.76]). Intensive care was more likely among IC patients 65-79 years (aOR [95% CI]: 1.25 [1.06-1.48]) and >80 years (aOR [95% CI]: 1.35 [1.06-1.73]) compared with non-IC patients in those age groups. IC patients were hospitalized longer (adjusted hazard ratio of discharge [95% CI]: 0.86 [0.83-0.88]) and were more likely to require mechanical ventilation (aOR [95% CI] 1.19 [1.05-1.36]). CONCLUSIONS: Substantial morbidity and mortality occurred among IC adults hospitalized with influenza. Influenza vaccination and antiviral administration could be increased in both IC and non-IC adults. |
Update: Influenza activity in the United States during the 2018-19 season and composition of the 2019-20 influenza vaccine
Xu X , Blanton L , Elal AIA , Alabi N , Barnes J , Biggerstaff M , Brammer L , Budd AP , Burns E , Cummings CN , Garg S , Kondor R , Gubareva L , Kniss K , Nyanseor S , O'Halloran A , Rolfes M , Sessions W , Dugan VG , Fry AM , Wentworth DE , Stevens J , Jernigan D . MMWR Morb Mortal Wkly Rep 2019 68 (24) 544-551 Influenza activity* in the United States during the 2018-19 season (September 30, 2018-May 18, 2019) was of moderate severity (1). Nationally, influenza-like illness (ILI)(dagger) activity began increasing in November, peaked during mid-February, and returned to below baseline in mid-April; the season lasted 21 weeks,( section sign) making it the longest season in 10 years. Illness attributed to influenza A viruses predominated, with very little influenza B activity. Two waves of influenza A were notable during this extended season: influenza A(H1N1)pdm09 viruses from October 2018 to mid-February 2019 and influenza A(H3N2) viruses from February through May 2019. Compared with the 2017-18 influenza season, rates of hospitalization this season were lower for adults, but were similar for children. Although influenza activity is currently below surveillance baselines, testing for seasonal influenza viruses and monitoring for novel influenza A virus infections should continue year-round. Receiving a seasonal influenza vaccine each year remains the best way to protect against seasonal influenza and its potentially severe consequences. |
Birth cohort effects in influenza surveillance data: Evidence that first influenza infection affects later influenza-associated illness
Budd AP , Beacham L , Smith CB , Garten RJ , Reed C , Kniss K , Mustaquim D , Ahmad FB , Cummings CN , Garg S , Levine MZ , Fry AM , Brammer L . J Infect Dis 2019 220 (5) 820-829 BACKGROUND: The evolution of influenza A viruses results in birth cohorts that have different initial influenza virus exposures. Historically, A/H3 predominant seasons have been associated with more severe influenza-associated disease; however, since the 2009 pandemic there are suggestions that some birth cohorts experience more severe illness in A/H1 predominant seasons. METHODS: U.S. influenza virologic, hospitalization and mortality surveillance data during 2000-2017 were analyzed for cohorts born between 1918 and 1989 that likely had different initial influenza virus exposures based on viruses circulating during early childhood. Relative risk/rate during H3 compared to H1 predominant seasons during pre-pandemic versus pandemic and later periods were calculated for each cohort. RESULTS: During the pre-pandemic period, all cohorts had more influenza-associated disease during H3 predominant seasons than H1 predominant seasons. During the pandemic and later period, four cohorts had higher hospitalization and mortality rates during H1 predominant seasons than H3 predominant seasons. DISCUSSION: Birth cohort differences in risk of influenza-associated disease by influenza A virus subtype can be seen in U.S. influenza surveillance data and differ between pre-pandemic and pandemic and later periods. As the population ages, the amount of influenza-associated disease may be greater in future H1 predominant seasons than H3 predominant seasons. |
Update: Influenza activity - United States, September 30, 2018-February 2, 2019
Blanton L , Dugan VG , Abd Elal AI , Alabi N , Barnes J , Brammer L , Budd AP , Burns E , Cummings CN , Garg S , Garten R , Gubareva L , Kniss K , Kramer N , O'Halloran A , Reed C , Rolfes M , Sessions W , Taylor C , Xu X , Fry AM , Wentworth DE , Katz J , Jernigan D . MMWR Morb Mortal Wkly Rep 2019 68 (6) 125-134 CDC collects, compiles, and analyzes data on influenza activity and viruses in the United States. During September 30, 2018-February 2, 2019,* influenza activity(dagger) in the United States was low during October and November, increased in late December, and remained elevated through early February. As of February 2, 2019, this has been a low-severity influenza season (1), with a lower percentage of outpatient visits for influenza-like illness (ILI), lower rates of hospitalization, and fewer deaths attributed to pneumonia and influenza, compared with recent seasons. Influenza-associated hospitalization rates among children are similar to those observed in influenza A(H1N1)pdm09 predominant seasons; 28 influenza-associated pediatric deaths occurring during the 2018-19 season have been reported to CDC. Whereas influenza A(H1N1)pdm09 viruses predominated in most areas of the country, influenza A(H3N2) viruses have predominated in the southeastern United States, and in recent weeks accounted for a growing proportion of influenza viruses detected in several other regions. Small numbers of influenza B viruses (<3% of all influenza-positive tests performed by public health laboratories) also were reported. The majority of the influenza viruses characterized antigenically are similar to the cell culture-propagated reference viruses representing the 2018-19 Northern Hemisphere influenza vaccine viruses. Health care providers should continue to offer and encourage vaccination to all unvaccinated persons aged >/=6 months as long as influenza viruses are circulating. Finally, regardless of vaccination status, it is important that persons with confirmed or suspected influenza who have severe, complicated, or progressive illness; who require hospitalization; or who are at high risk for influenza complications be treated with antiviral medications. |
Clinical features and outcomes of immunocompromised children hospitalized with laboratory-confirmed influenza in the United States, 2011-2015
Collins JP , Campbell AP , Openo K , Farley MM , Cummings CN , Kirley PD , Herlihy R , Yousey-Hindes K , Monroe ML , Ladisky M , Lynfield R , Baumbach J , Spina N , Bennett N , Billing L , Thomas A , Schaffner W , Price A , Garg S , Anderson EJ . J Pediatric Infect Dis Soc 2018 8 (6) 539-549 Background: Existing data on the clinical features and outcomes of immunocompromised children with influenza are limited. Methods: Data from the 2011-2012 through 2014-2015 influenza seasons were collected as part of the Centers for Disease Control and Prevention (CDC) Influenza Hospitalization Surveillance Network (FluSurv-NET). We compared clinical features and outcomes between immunocompromised and nonimmunocompromised children (<18 years old) hospitalized with laboratory-confirmed community-acquired influenza. Immunocompromised children were defined as those for whom >/=1 of the following applies: human immunodeficiency virus/acquired immunodeficiency syndrome, cancer, stem cell or solid organ transplantation, nonsteroidal immunosuppressive therapy, immunoglobulin deficiency, complement deficiency, asplenia, and/or another rare condition. The primary outcomes were intensive care admission, duration of hospitalization, and in-hospital death. Results: Among 5262 hospitalized children, 242 (4.6%) were immunocompromised; receipt of nonsteroidal immunosuppressive therapy (60%), cancer (39%), and solid organ transplantation (14%) were most common. Immunocompromised children were older than the nonimmunocompromised children (median, 8.8 vs 2.8 years, respectively; P < .001), more likely to have another comorbidity (58% vs 49%, respectively; P = .007), and more likely to have received an influenza vaccination (58% vs 39%, respectively; P < .001) and early antiviral treatment (35% vs 27%, respectively; P = .013). In multivariable analyses, immunocompromised children were less likely to receive intensive care (adjusted odds ratio [95% confidence interval], 0.31 [0.20-0.49]) and had a slightly longer duration of hospitalization (adjusted hazard ratio of hospital discharge [95% confidence interval], 0.89 [0.80-0.99]). Death was uncommon in both groups. Conclusions: Immunocompromised children hospitalized with influenza received intensive care less frequently but had a longer hospitalization duration than nonimmunocompromised children. Vaccination and early antiviral use could be improved substantially. Data are needed to determine whether immunocompromised children are more commonly admitted with milder influenza severity than are nonimmunocompromised children. |
Update: Influenza Activity in the United States During the 2017-18 Season and Composition of the 2018-19 Influenza Vaccine.
Garten R , Blanton L , Elal AIA , Alabi N , Barnes J , Biggerstaff M , Brammer L , Budd AP , Burns E , Cummings CN , Davis T , Garg S , Gubareva L , Jang Y , Kniss K , Kramer N , Lindstrom S , Mustaquim D , O'Halloran A , Sessions W , Taylor C , Xu X , Dugan VG , Fry AM , Wentworth DE , Katz J , Jernigan D . MMWR Morb Mortal Wkly Rep 2018 67 (22) 634-642 ![]() ![]() The United States 2017-18 influenza season (October 1, 2017-May 19, 2018) was a high severity season with high levels of outpatient clinic and emergency department visits for influenza-like illness (ILI), high influenza-related hospitalization rates, and elevated and geographically widespread influenza activity across the country for an extended period. Nationally, ILI activity began increasing in November, reaching an extended period of high activity during January-February, and remaining elevated through March. Influenza A(H3N2) viruses predominated through February and were predominant overall for the season; influenza B viruses predominated from March onward. This report summarizes U.S. influenza activity* during October 1, 2017-May 19, 2018.(dagger). |
Update: Influenza activity - United States, October 1, 2017-February 3, 2018
Budd AP , Wentworth DE , Blanton L , Elal AIA , Alabi N , Barnes J , Brammer L , Burns E , Cummings CN , Davis T , Flannery B , Fry AM , Garg S , Garten R , Gubareva L , Jang Y , Kniss K , Kramer N , Lindstrom S , Mustaquim D , O'Halloran A , Olsen SJ , Sessions W , Taylor C , Xu X , Dugan VG , Katz J , Jernigan D . MMWR Morb Mortal Wkly Rep 2018 67 (6) 169-179 Influenza activity in the United States began to increase in early November 2017 and rose sharply from December through February 3, 2018; elevated influenza activity is expected to continue for several more weeks. Influenza A viruses have been most commonly identified, with influenza A(H3N2) viruses predominating, but influenza A(H1N1)pdm09 and influenza B viruses were also reported. This report summarizes U.S. influenza activity* during October 1, 2017-February 3, 2018,(dagger) and updates the previous summary (1). |
Update: Influenza activity - United States, October 1-November 25, 2017
Dugan VG , Blanton L , Elal AIA , Alabi N , Barnes J , Brammer L , Burns E , Cummings CN , Davis T , Flannery B , Fry AM , Garg S , Garten R , Gubareva L , Jang Y , Kniss K , Kramer N , Lindstrom S , Mustaquim D , O'Halloran A , Olsen SJ , Sessions W , Taylor C , Trock S , Xu X , Wentworth DE , Katz J , Jernigan D . MMWR Morb Mortal Wkly Rep 2017 66 (48) 1318-1326 Influenza activity in the United States was low during October 2017, but has been increasing since the beginning of November. Influenza A viruses have been most commonly identified, with influenza A(H3N2) viruses predominating. Several influenza activity indicators were higher than is typically seen for this time of year. The majority of influenza viruses characterized during this period were genetically or antigenically similar to the 2017-18 Northern Hemisphere cell-grown vaccine reference viruses. These data indicate that currently circulating viruses have not undergone significant antigenic drift; however, circulating A(H3N2) viruses are antigenically less similar to egg-grown A(H3N2) viruses used for producing the majority of influenza vaccines in the United States. It is difficult to predict which influenza viruses will predominate in the 2017-18 influenza season; however, in recent past seasons in which A(H3N2) viruses predominated, hospitalizations and deaths were more common, and the effectiveness of the vaccine was lower. Annual influenza vaccination is recommended for all persons aged ≥6 months who do not have contraindications. Multiple influenza vaccines are approved and recommended for use during the 2017-18 season, and vaccination should continue to be offered as long as influenza viruses are circulating and unexpired vaccine is available. This report summarizes U.S. influenza activity* during October 1-November 25, 2017 (surveillance weeks 40-47).(dagger). |
Social determinants of influenza hospitalization in the United States
Chandrasekhar R , Sloan C , Mitchel E , Ndi D , Alden N , Thomas A , Bennett NM , Kirley PD , Hill M , Anderson EJ , Lynfield R , Yousey-Hindes K , Bargsten M , Zansky SM , Lung K , Schroeder M , Monroe M , Eckel S , Markus TM , Cummings CN , Garg S , Schaffner W , Lindegren ML . Influenza Other Respir Viruses 2017 11 (6) 479-488 BACKGROUND: Influenza hospitalizations result in substantial morbidity and mortality each year. Little is known about the association between influenza hospitalization and census tract-based socioeconomic determinants beyond the effect of individual factors. OBJECTIVE: To evaluate if census tract-based determinants such as poverty and household crowding would contribute significantly to the risk of influenza hospitalization above and beyond individual level determinants. METHODS: We analyzed 33,515 laboratory-confirmed influenza-associated hospitalizations that occurred during the 2009-2010 through 2013-2014 influenza seasons using a population-based surveillance system at 14 sites across the United States. RESULTS: Using a multilevel regression model, we found that individual factors were associated with influenza hospitalization with the highest adjusted odds ratio (AOR) of 9.20 (95% CI 8.72-9.70) for those >=65 versus 5-17 years old. African Americans had an AOR of 1.67 (95% CI 1.60-1.73) compared to Whites, and Hispanics had an AOR of 1.21 (95% CI 1.16-1.26) compared to non-Hispanics. Among census tract-based determinants, those living in a tract with >=20% versus <5% of persons living below poverty had an AOR of 1.31 (95% CI 1.16-1.47), those living in a tract with >=5% versus <5% of persons living in crowded conditions had an AOR of 1.17 (95% CI 1.11-1.23) and those living in a tract with >=40% versus <5% female heads of household had an AOR of 1.32 (95% CI 1.25-1.40). CONCLUSION: Census tract-based determinants account for 11% of the variability in influenza hospitalization. This article is protected by copyright. All rights reserved. |
Update: Influenza activity in the United States during the 2016-17 season and composition of the 2017-18 influenza vaccine
Blanton L , Alabi N , Mustaquim D , Taylor C , Kniss K , Kramer N , Budd A , Garg S , Cummings CN , Chung J , Flannery B , Fry AM , Sessions W , Garten R , Xu X , Elal AIA , Gubareva L , Barnes J , Dugan V , Wentworth DE , Burns E , Katz J , Jernigan D , Brammer L . MMWR Morb Mortal Wkly Rep 2017 66 (25) 668-676 During the 2016-17 influenza season (October 2, 2016-May 20, 2017) in the United States, influenza activity* was moderate. Activity remained low through November, increased during December, and peaked in February nationally, although there were regional differences in the timing of influenza activity. Influenza A(H3N2) viruses predominated through mid-March and were predominant overall for the season, but influenza B viruses were most commonly reported from late March through May. This report summarizes influenza activity in the United States during October 2, 2016-May 20, 2017dagger and updates the previous summary (1). |
Update: Influenza activity - United States, October 2, 2016-February 4, 2017
Blanton L , Mustaquim D , Alabi N , Kniss K , Kramer N , Budd A , Garg S , Cummings CN , Fry AM , Bresee J , Sessions W , Garten R , Xu X , Elal AI , Gubareva L , Barnes J , Wentworth DE , Burns E , Katz J , Jernigan D , Brammer L . MMWR Morb Mortal Wkly Rep 2017 66 (6) 159-166 This report summarizes U.S. influenza activity during October 2, 2016-February 4, 2017, and updates the previous summary. Influenza activity in the United States began to increase in mid-December, remained elevated through February 4, 2017, and is expected to continue for several more weeks. To date, influenza A (H3N2) viruses have predominated overall, but influenza A (H1N1)pdm09 and influenza B viruses have also been identified. |
Update: Influenza activity - United States, October 2-December 17, 2016
Shang M , Blanton L , Kniss K , Mustaquim D , Alabi N , Barnes S , Budd A , Davlin SL , Kramer N , Garg S , Cummings CN , Flannery B , Fry AM , Grohskopf LA , Olsen SJ , Bresee J , Sessions W , Garten R , Xu X , Elal AI , Gubareva L , Barnes J , Wentworth DE , Burns E , Katz J , Jernigan D , Brammer L . MMWR Morb Mortal Wkly Rep 2016 65 (5051) 1439-1444 This report summarizes U.S. influenza activity during October 2-December 17, 2016. Influenza activity in the United States remained low in October and has been slowly increasing since November. Influenza A viruses were identified most frequently, with influenza A (H3N2) viruses predominating. Most influenza viruses characterized during this period were genetically or antigenically similar to the reference viruses representing vaccine components recommended for production in the 2016-17 Northern Hemisphere influenza vaccines. |
Influenza activity - United States, 2015-16 season and composition of the 2016-17 influenza vaccine
Davlin SL , Blanton L , Kniss K , Mustaquim D , Smith S , Kramer N , Cohen J , Cummings CN , Garg S , Flannery B , Fry AM , Grohskopf LA , Bresee J , Wallis T , Sessions W , Garten R , Xu X , Elal AI , Gubareva L , Barnes J , Wentworth DE , Burns E , Katz J , Jernigan D , Brammer L . MMWR Morb Mortal Wkly Rep 2016 65 (22) 567-575 During the 2015-16 influenza season (October 4, 2015-May 21, 2016) in the United States, influenza activity was lower and peaked later compared with the previous three seasons (2012-13, 2013-14, and 2014-15). Activity remained low from October 2015 until late December 2015 and peaked in mid-March 2016. During the most recent 18 influenza seasons (including this season), only two other seasons have peaked in March (2011-12 and 2005-06). Overall influenza activity was moderate this season, with a lower percentage of outpatient visits for influenza-like illness (ILI), lower hospitalization rates, and a lower percentage of deaths attributed to pneumonia and influenza (P&I) compared with the preceding three seasons. Influenza A(H1N1)pdm09 viruses predominated overall, but influenza A(H3N2) viruses were more commonly identified from October to early December, and influenza B viruses were more commonly identified from mid-April through mid-May. The majority of viruses characterized this season were antigenically similar to the reference viruses representing the recommended components of the 2015-16 Northern Hemisphere influenza vaccine. This report summarizes influenza activity in the United States during the 2015-16 influenza season (October 4, 2015-May 21, 2016) section sign and reports the vaccine virus components recommended for the 2016-17 Northern Hemisphere influenza vaccines. |
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