BACKGROUND: Influenza contributes to a high burden of pediatric emergency department (ED) visits annually. Guidelines recommend outpatient antiviral treatment for children at higher risk of severe influenza and recommend considering treatment for those who present within 2 days of symptom onset. We describe antiviral prescription in children with influenza presenting to the ED. METHODS: We analyzed data from the New Vaccine Surveillance Network (2016-2020), including children presenting to the ED and enrolled with confirmed influenza at one of seven pediatric academic centers. We compared characteristics of children prescribed antivirals to those who were not, using generalized estimating equations models to identify predictors of antiviral prescription. Children were considered at higher risk of severe influenza if they were < 5 years old or had an underlying condition. RESULTS: Overall, 2472 (15%) of 16,915 enrolled children tested positive for influenza virus. Among these, 1931 (78%) were at higher risk of severe influenza; only 622 (32%) received an antiviral. Among 233 (9%) children not at high risk with symptom onset ≤ 2 days, 62 (27%) were prescribed an antiviral. Children prescribed an antiviral had a shorter duration of illness prior to presenting to the ED. For children at higher risk of severe influenza, odds of antiviral prescription were higher for those clinically tested for influenza and with underlying conditions. CONCLUSION: Clinical testing and having an underlying condition were associated with antiviral prescription in children at higher risk of severe influenza. However, only 1/3 of those at higher risk were prescribed an antiviral. Strategies to increase antiviral use for children at higher risk for influenza in the ED are needed.

Hand hygiene (HH) can prevent the spread of infectious diseases and school absenteeism. However, limited data exist on HH practices at schools. Our study assesses the impact of a pilot HH intervention in 12 schools in Belize during the coronavirus disease 2019 (COVID-19) pandemic. After a national assessment of existing water, sanitation, and hygiene resources (December 2021-January 2022), 12 pilot schools were selected to evaluate an HH intervention, which included environmental nudges and HH education. Baseline assessments occurred in March 2022, the HH intervention was implemented during October 2022-May 2023, and follow-up assessments were conducted in June 2023. Student knowledge, attitudes, practices (KAP), and hand dirtiness were assessed at baseline and follow-up. There were no changes in overall KAP median scores between the baseline and the follow-up surveys (knowledge: 3 of 4; attitudes: 11 of 12; practices: 8 of 8). There was an increase in the proportion of students who reported cleaning hands during critical moments, such as before eating and after using the restroom. Observations showed that 83% of students at baseline and 71% of students at follow-up washed their hands with soap after using the restroom. The median hand dirtiness score was seven at baseline and five at follow-up (lower score corresponds to dirtier hands). We did not observe improvements in HH after the intervention. It is possible that the decrease in perceived risk of infection as COVID-19 protocols from baseline to follow-up were reduced in schools contributed to the decrease in HH practices.

BACKGROUND: In November, 2020, WHO authorised novel oral polio vaccine type 2 (nOPV2) use under Emergency Use Listing in response to outbreaks of circulating vaccine-derived poliovirus type 2 (cVDPV2). Although no concerns were identified in nOPV2 trials, the Global Advisory Committee on Vaccine Safety requested more extensive vaccine safety data during emergency use. The Uganda Ministry of Health declared a cVDPV2 outbreak in 2021 and responded with an nOPV2 campaign in January, 2022. More than 9 million children aged 0-59 months were vaccinated, providing an opportunity to generate robust safety data. METHODS: We monitored the safety of nOPV2 for 42 days post-vaccination using: routine passive surveillance for adverse events following immunisation (AEFI); ongoing acute flaccid paralysis (AFP) surveillance; active, hospital-based surveillance for pre-specified adverse events of special interest (AESI); and active, cohort event monitoring. AFP cases were reviewed by the National Polio Expert Committee. Serious AEFI and all AESI and AFP cases with nOPV2 receipt underwent causality assessment by the National AEFI Committee. FINDINGS: Across surveillance systems, 1128 children vaccinated with nOPV2 experienced one or more AEFI: 43 children identified through passive surveillance, 128 suspected AFP cases, five AESI cases, and 952 children with reported AEFI through cohort event monitoring. Overall, 109 adverse events were considered serious; six (fever, gastroenteritis (n=3), acute disseminated encephalomyelitis, and encephalitis) were determined by the National AEFI Committee to be consistent with causal association to immunisation with nOPV2. No cases of vaccine-associated paralytic poliomyelitis were detected. One death was detected, considered inconsistent with causal association to immunisation with nOPV2, per the National AEFI Committee. INTERPRETATION: No new safety concerns were identified with nOPV2 use in Uganda following a national vaccination campaign, providing valuable data that informed WHO prequalification and product licensure. FUNDING: Centers for Disease Control and Prevention. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

BACKGROUND: Risk factors for severe respiratory syncytial virus (RSV) illness include early infancy, premature birth, and underlying medical conditions. However, the clinical significance of respiratory viral co-detection is unclear. We compared the clinical outcomes of young children with RSV-only detection and those with RSV viral co-detection. METHODS: We conducted active, population-based surveillance of children with medically attended fever or respiratory symptoms at 7 US medical centers (1 December 2016-31 March 2020). Demographic and clinical data were collected through parental interviews and chart abstractions. Nasal swabs, with or without throat swabs, were systematically tested for RSV and 6 other common respiratory virus groups. We compared clinical outcomes, including hospitalization, and among those hospitalized, length of stay, intensive care unit admission, supplemental oxygen use, and intubation, between children aged <2 years with RSV-only detection and those with RSV co-detection. RESULTS: We enrolled 18 008 children aged <2 years. Of 17 841 (99.1%) tested for RSV, 5099 (28.6%) were positive. RSV was singly detected in 3927 children (77.0%) and co-detected in 1172 (23.0%). RSV co-detection with parainfluenza virus or adenovirus was associated with significantly lower odds of hospitalization (adjusted odds ratio, 0.56; 95% confidence interval [CI]: .33-.95; P = .031) and supplemental oxygen use (adjusted odds ratio, 0.66; 95% CI: .46-.95; P = .026), respectively, than RSV-only detection. For all other comparisons, we did not identify a significant association between RSV co-detection and worse clinical outcomes. CONCLUSIONS: Co-detection of RSV with another respiratory virus was not significantly associated with worse clinical outcomes compared with RSV-only detection.

IMPORTANCE: Enterovirus D68 (EV-D68) typically causes mild to severe acute respiratory illness (ARI). Testing and surveillance for EV-D68 in the US are limited, and important epidemiologic gaps remain. OBJECTIVE: To characterize the epidemiology and clinical severity of EV-D68 among US children seeking care for ARI from 2017 to 2022, using a multisite, active, systematic surveillance network. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study collected data from the New Vaccine Surveillance Network, an active, prospective, population-based surveillance system of emergency departments (EDs) and hospitals at 7 US academic medical centers. Children with ARI and EV-D68-positive results were enrolled during platform-wide EV-D68 testing periods (July to October 2017, July to November 2018, July to November 2020, and July 2021 to December 2022). Included children were aged younger than 18 years, reported 1 or more qualifying ARI symptoms, with a symptom duration less than 14 days at enrollment. Data were analyzed from in October 2024. EXPOSURES: Laboratory-confirmed EV-D68 infection, including overall infections or those without viral codetection. MAIN OUTCOMES AND MEASURES: Trends and characteristics of EV-D68, including demographics, underlying conditions, and clinical severity by health care setting, were explored. Among hospitalized children with EV-D68-positive results without viral codetection, multivariable logistic regression was used to examine factors associated with receipt of (1) supplemental oxygen or (2) intensive care. RESULTS: From 2017 to 2022, 976 children with EV-D68-positive results were identified (median [IQR] age, 47 [18-63] months; 391 [40.1%] female); most were enrolled in 2018 (382 children) and 2022 (533 children). Among these, 856 had no viral codetection, of which 320 were discharged home from the ED (median [IQR] age, 33 [16-59] months; 180 male [56.3%]; 237 [74.1%] with no reported underlying conditions) and 536 were hospitalized (median [IQR] age, 40 [19-69] months; 330 male [61.6%]; 268 [50.0%] with no reported underlying conditions). Among those hospitalized, 199 (37.1%) reported a history of asthma or reactive airway disease (RAD) and 77 (14.4%) reported a condition other than asthma or RAD. Having an underlying condition other than asthma or RAD was associated with increased odds of receiving supplemental oxygen (adjusted odds ratio, 2.72; 95% CI, 1.43-5.18) or intensive care admission (adjusted odds ratio, 3.09; 95% CI, 1.72-5.56); neither age group nor history of asthma or RAD were associated with oxygen receipt or intensive care admission. CONCLUSIONS AND RELEVANCE: In this cross-sectional study of children with medically attended EV-D68 infections, EV-D68 was associated with severe disease in otherwise healthy children of all ages, and children with nonasthma or RAD comorbidities were at higher risk for severe outcomes when hospitalized.

Maternal respiratory syncytial virus (RSV) vaccine and nirsevimab, a long-acting monoclonal antibody for infants aged 0-7 months and children aged 8-19 months who are at increased risk for severe RSV disease, became widely available for prevention of severe RSV disease among infants and young children during the 2024-25 RSV season. To evaluate the association between availability of these products and infant and child RSV-associated hospitalization rates, the rates among children aged <5 years were compared for the 2024-25 and 2018-20 RSV seasons using data from the RSV-Associated Hospitalization Surveillance Network (RSV-NET) and New Vaccine Surveillance Network (NVSN). Among infants aged 0-7 months (eligible for protection with maternal vaccination or nirsevimab), 2024-25 RSV-associated hospitalization rates were lower compared with 2018-20 pooled rates (estimated relative rate reductions of 43% [RSV-NET: 95% CI = 40%-46%] and 28% [NVSN: 95% CI = 18%-36%]). The largest estimated rate reduction was observed among infants aged 0-2 months (RSV-NET: 52%, 95% CI = 49%-56%; NVSN: 45%, 95% CI = 32%-57%) and during peak hospitalization periods (December-February). These findings support Advisory Committee on Immunization Practices' recommendations for maternal vaccination or nirsevimab to protect against severe RSV disease in infants and highlight the importance of implementing the recommendations to protect infants as early in the RSV season as possible, before peak transmission, and for infants born during the RSV season, within the first week of life, ideally during the birth hospitalization.

On September 20, 2022, the Uganda Ministry of Health declared an outbreak of Sudan Virus Disease (SVD). As the outbreak grew, it became imperative to quickly visualize and analyze chains of disease transmission. Determining epidemiological links between cases is critical for outbreak control as incorrect linkages may result in missed case detection and undetected disease transmission. We describe the Uganda Ministry of Health's experience using Chainchecker, a computer application designed to visualize and verify transmission chain data. To use Chainchecker, a line list documenting the epidemiological details associated with individual cases is uploaded to the application. To verify epidemiologic linkages, the application calculates the exposure windows for each case based on user-defined incubation periods and dates of symptom onset. If genetic sequencing data is available, Chainchecker can overlay genetic distance data on top of the epidemiologic data. Chainchecker can also provide visualizations of hospitalization data, which can highlight potential instances of nosocomial disease transmission. Using the Chainchecker application, the case investigation team was able to connect 11 previously unlinked cases to the larger chain of disease transmission. The use of the application also led to the identification and correction of transmission chain errors for 13 SVD cases and the identification of 5 potential instances of nosocomial transmission. The use of the Chainchecker application in Uganda during the 2022 SVD outbreak allowed the response teams to rectify critical errors in transmission chains. Countries prone to Ebola Disease (EBOD) outbreaks should consider incorporating Chainchecker as an element of EBOD preparedness and response.

Foodborne hepatitis A illnesses and outbreaks have been associated with consumption of ready-to-eat foods contaminated with the feces of person(s) shedding hepatitis A virus (HAV). Outbreaks have been linked to fresh and frozen produce imported from countries where HAV is endemic, hygiene and sanitation are inadequate, or food safety standards are lacking or unenforced. In 2022 and 2023, federal, state, and international partners investigated two multijurisdictional outbreaks of infections involving the same HAV genotype IA strain linked to fresh and frozen organic strawberries sourced from a single grower in Baja California, Mexico. These resulted in 39 reported cases in the U.S. and Canada, 21 hospitalizations, and no reported deaths. The United States Food and Drug Administration (FDA), Canadian Food Inspection Agency, and U.S. state partners conducted traceback investigations for fresh strawberries in 2022, while FDA and U.S. state partners traced back frozen strawberries in 2023. Based on the traceback investigations, implicated strawberries were harvested during the 2022 growing season and sold to fresh and frozen berry markets. During a farm inspection in Mexico in 2023, gaps were observed in agricultural practices that could have contributed to contamination of strawberries with HAV. FDA did not detect HAV in the two frozen strawberry samples linked to the recalled lots or environmental water samples collected at the implicated grower in 2023; no samples were collected during the 2022 investigation. Indicator organisms associated with human fecal contamination (male-specific coliphage and crAssphge) were detected in environmental water. Challenges in these investigations included limited recall of food exposures, exposures associated with multiple purchase dates, commingling of strawberries within the frozen market supply chains, and complexities with communicating these outbreak investigations to the public.

The Marie Skłodowska-Curie Symposia on Cancer Research and Care (MSCS-CRC) promote collaborations between cancer researchers and care providers in the United States, Canada and Central and Eastern European Countries (CEEC) to accelerate the development of new cancer therapies, new strategies for early detection and prevention, and improve cancer care and the quality of life for patients and their families. The 4th MSCS-CRC (September 25-27, 2024, Buffalo, New York) brought together 147 participants from the US, Canada, Croatia, Czechia, Lithuania, Poland, Romania and Ukraine, and involved representatives of the US Centers for Disease Control and Prevention (CDC), National Cancer Institute (NCI) and their counterparts from Poland, Ukraine Lithuania and other CEECs. They were accompanied by New York State (NYS) and local representatives of the NYS Empire State Development, and of the Translational Research Consortium of Cancer Centers (TRCCC), involving 13 cancer centers from the Northeastern US and Canada, as well as several Pharma and Biotech companies. The 4th Meeting focused on prevention and early detection of smoking- and HPV-related cancers, reducing disparities in cancer detection-, care and outcomes, and increasing the feasibility and reducing costs of high-end treatments, such as cell therapies for patients with advanced cancers. The second focus area were the available sources of funding of regional and international collaborations in these areas. The relevance of the successful model TRCC to promoting the oncology training and research collaborations in the CEE Countries was discussed. The 5th MSCR-CRC meeting will take place September 3-5, 2025, in Warsaw, Poland.

BACKGROUND: Human parainfluenza viruses (PIV) are a major cause of acute respiratory infection (ARI) leading to hospitalization in young children. In order to quantify the burden of PIV hospitalizations and to evaluate the characteristics of children hospitalized with PIV by virus type, we used data from the New Vaccine Surveillance Network (NVSN), a multicenter, active, prospective population-based surveillance network, enrolling children hospitalized for ARI (defined as fever and/or respiratory symptoms) at 7 U.S. children's hospitals. METHODS: The study period included December 1, 2016 through March 31, 2020. Data captured included demographic characteristics, clinical presentation, underlying medical conditions, discharge diagnoses, and virus detection by RT-PCR. Linear and logistic regression were used to compare descriptive and clinical characteristics among children. Population-based PIV-associated hospitalization rates were calculated by age group and PIV-type. RESULTS: Of the 16,791 enrolled children with PIV virologic testing, 10,488 had only one respiratory virus detected, among whom 702 (7%) had positive testing for PIV without a co-detected virus (mean age [SD], 2.2 [3.2] years). Of these 702 children, 340 (48%) had underlying comorbidities, 139 (20%) had a history of prematurity, 121 (17%) were admitted to the ICU, and 23 (3%) required intubation. Overall, PIV hospitalization rates were highest in children aged 0-5 months (1.91 hospitalizations per 1,000 children per year [95% CI, 1.61-2.23], with PIV-3 contributing to the highest rates in that age group, followed by PIV-1 and PIV-4: 1.08 [0.84-1.21], 0.42 [0.28-0.58] and 0.25 [0.15-0.37] per 1,000 children per year, respectively. Seasonal distribution of PIV-associated hospitalizations varied by type. CONCLUSIONS: PIV infection was associated with a substantial number of ARI hospitalizations in children aged 0-5 months. Results suggest that future PIV prevention strategies in the US that focus on younger children and protection against PIV-3, PIV-1, and PIV-4 might have the greatest impact on reducing PIV hospitalization burden.

BACKGROUND: Uzbekistan, a highly endemic country for hepatitis B virus (HBV), introduced infant vaccination with hepatitis B vaccine (HepB) in 2001. Since 2002, it had ≥90 % reported immunization coverage for ≥3 doses of HepB (HepB3) and the birth dose (HepB-BD). However, the impact of HepB vaccination and the progress towards achieving the regional hepatitis B control and global viral hepatitis B elimination goals had not been assessed. METHODS: To determine current HBsAg prevalence among children in Uzbekistan, in 2022, we conducted a nationwide serosurvey among schoolchildren (grades 1-3) using a stratified, multi-stage cluster design. Participants' basic demographics and HepB immunization information were obtained. Blood specimens were tested for HBsAg using a WHO-prequalified rapid test (Bioline HBsAg WB, Abbott Diagnostics). Samples with positive and indeterminate results were tested for HBsAg by ELISA (Murex HBsAg Version3, Diasorine). Weighted proportions and adjusted 95 % confidence intervals (CI) were calculated. RESULTS: Of 4119 children enrolled in 148 schools, blood was collected from 3753 (91.1 %) and immunization data were available for 3833 (93.3 %). National HBsAg prevalence was 0.20 % (adjusted 95 % CI, 0.09 %-0.38 %). Among children with available immunization data, 97.7 % (97.2 %-98.1 %) received ≥3 HepB doses and 94.9 % (94.1 %-95.5 %) received HepB-BD, including timely HepB-BD in 93.7 % (92.9 %-94.5 %). CONCLUSIONS: The survey demonstrated that Uzbekistan has met the <0.5 % European regional HBsAg seroprevalence target and has made substantial progress towards meeting the <0.1 % HBsAg seroprevalence target for the elimination of HBV mother to-child transmission (MTCT). Based on these findings and ≥ 90 % HepB-BD and HepB3 coverage, in 2023, Uzbekistan was validated as having achieved the regional hepatitis B control goal. To achieve the elimination of MTCT of HBV, additional interventions, including improving antenatal screening for HBsAg, providing antiviral treatment of eligible HBsAg-positive pregnant women and hepatitis B immunoglobulin to infants born to HBsAg-positive mothers, should be considered.

BACKGROUND: Pediatric respiratory syncytial virus (RSV)-related acute lower respiratory tract infection (LRTI) commonly requires hospitalization. The Clinical Progression Scale Pediatrics (CPS-Ped) measures level of respiratory support and degree of hypoxia across a range of disease severity, but it has not been applied in infants hospitalized with severe RSV-LRTI. METHODS: We analyzed data from a prospective surveillance registry of infants hospitalized for RSV-related complications across 39 U.S. PICUs from October through December 2022. We assigned CPS-Ped (0=discharged home at respiratory baseline to 8=death) at admission, days 2-7,10, and 14. We identified predictors of clinical improvement (CPS-Ped≤2 or 3-point decrease) by day 7 using multivariable log-binomial regression models and estimated the sample size (80% power) to detect 15% between-group clinical improvement with CPS-Ped versus hospital length of stay (LOS). RESULTS: Of 585 hospitalized infants, 138 (23.6%) received invasive mechanical ventilation (IMV). Of the 49 (8.4%) infants whose CPS-Ped score worsened by 2 points after admission, one died. Failure to clinically improve by day 7 occurred in 205 (35%) infants and was associated with age <3 months, prematurity, underlying respiratory condition, and IMV in the first 24 hours in the multivariable analysis. The estimated sample size per arm required for detecting a 15% clinical improvement in a potential study was 584 using CPS-Ped clinical improvement versus 2,031 for hospital LOS. CONCLUSIONS: CPS-Ped can be used to capture a range of disease severity and track clinical improvement in infants who develop RSV-related critical illness and could be useful for evaluating therapeutic interventions for RSV.

IMPORTANCE: Increasing the understanding of vaccine effectiveness (VE) against levels of severe influenza in children could help increase uptake of influenza vaccination and strengthen vaccine policies globally. OBJECTIVE: To investigate VE in children by severity of influenza illness. DESIGN, SETTING, AND PARTICIPANTS: This case-control study with a test-negative design used data from 8 participating medical centers located in geographically different US states in the New Vaccine Surveillance Network from November 6, 2015, through April 8, 2020. Participants included children 6 months through 17 years of age who were hospitalized or presented to an emergency department (ED) with acute respiratory illness. EXPOSURES: Receipt of at least 1 dose of the current season's influenza vaccine. MAIN OUTCOMES AND MEASURES: Demographic and clinical characteristics of patients presenting to the hospital or ED with or without influenza were recorded and grouped by influenza vaccination status. Estimated VE against severe influenza illness was calculated using multiple measures to capture illness severity. Data were analyzed between June 1, 2022, and September 30, 2023. RESULTS: Among 15 728 children presenting for care with acute respiratory illness (8708 [55.4%] male; 13 450 [85.5%] 6 months to 8 years of age and 2278 [14.5%] 9-17 years of age), 2710 (17.2%) had positive influenza tests and 13 018 (82.8%) had negative influenza tests (controls). Of the influenza test-positive cases, 1676 children (61.8%) had an ED visit, 896 children (33.1%) required hospitalization for noncritical influenza, and 138 children (5.1%) required hospitalization for critical influenza. About half (7779 [49.5%]) of the children (both influenza test positive and test negative) were vaccinated. Receiving at least 1 influenza vaccine dose was estimated to have a VE of 55.7% (95% CI, 51.6%-59.6%) for preventing influenza-associated ED visits or hospitalizations among children of all ages. The estimated VE was similar across severity levels: 52.8% (95% CI, 46.6%-58.3%) for ED visits, 52.3% (95% CI, 44.8%-58.8%) for noncritical hospitalization, and 50.4% (95% CI, 29.7%-65.3%) for critical hospitalization. CONCLUSIONS AND RELEVANCE: Findings from this case-control study with a test-negative design involving children with a spectrum of influenza severity suggest that influenza vaccination protects children against all levels of severe influenza illness.

BACKGROUND: Guidelines state that all hospitalized children with suspected or confirmed influenza receive prompt treatment with influenza-specific antivirals. We sought to determine the frequency of, and factors associated with, antiviral receipt among hospitalized children. METHODS: We conducted active surveillance of children presenting with fever or respiratory symptoms from 1 December 2016 to 31 March 2020 at 7 pediatric medical centers in the New Vaccine Surveillance Network. The cohort consisted of children hospitalized with influenza A or B confirmed by clinical or research testing. The primary outcome was frequency of antiviral receipt during hospitalization. We used logistic regression to obtain adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for factors associated with antiviral receipt. RESULTS: A total of 1213 children with laboratory-confirmed influenza were included. Overall, 652 children (53.8%) received an antiviral. Roughly 63.0% of children received clinical influenza testing. Among those with clinical testing, 67.4% received an antiviral. Factors associated with higher odds of antiviral receipt included hematologic (aOR = 1.76; 95% CI = 1.03-3.02) or oncologic/immunocompromising (aOR = 2.41; 95% CI = 1.13-5.11) disorders, prehospitalization antiviral receipt (aOR = 2.34; 95% CI = 1.49-3.67), clinical influenza testing (aOR = 3.07; 95% CI = 2.28-4.14), and intensive care unit admission (aOR = 1.53; 95% CI = 1.02-2.29). Symptom duration >2 days was associated with lower odds of antiviral treatment (aOR = 0.40; 95% CI = .30-.52). Antiviral receipt varied by site with a 5-fold difference across sites. CONCLUSIONS: Almost half of children hospitalized with influenza did not receive antivirals. Additional efforts to understand barriers to guideline adherence are crucial for optimizing care in children hospitalized with influenza.

IMPORTANCE: During the 2023-2024 respiratory syncytial virus (RSV) season in the United States, 2 new RSV prevention products were recommended to protect infants in their first RSV season: nirsevimab and Pfizer's maternal RSV vaccine. Postlicensure studies are needed to assess prevention product impact and effectiveness. OBJECTIVE: To compare the epidemiology and disease burden of medically attended RSV-associated acute respiratory illness (ARI) among children younger than 5 years during the 2023-2024 RSV season with 3 prepandemic RSV seasons (2017-2020), estimate nirsevimab effectiveness against medically attended RSV-associated ARI, and compare nirsevimab binding site mutations among circulating RSV in infants with and without nirsevimab receipt. DESIGN, SETTING, AND PARTICIPANTS: This study included a prospective population-based surveillance for medically attended ARI with systematic molecular testing for RSV and whole-genome sequencing of RSV positive samples, as well as a test-negative case-control design to estimate nirsevimab effectiveness. The study was conducted in 7 academic pediatric medical centers in the United States with data from RSV seasons (September 1 through April 30) in 2017 through 2024. Participants were children younger than 5 years with medically attended ARI. EXPOSURE: For the nirsevimab effectiveness analyses, nirsevimab receipt among infants younger than 8 months as of or born after October 1, 2023. MAIN OUTCOME AND MEASURE: Medically attended RSV-associated ARI. RESULTS: Overall, 28 689 children younger than 5 years with medically attended ARI were enrolled, including 9536 during September 1, 2023, through April 30, 2024, and 19 153 during the same calendar period of 2017-2020. Of these children, 16 196 (57%) were male, and 12 444 (43.4) were female; the median (IQR) age was 15 (6-29) months. During 2023-2024, the proportion of children with RSV was 23% (2199/9490) among all medically attended episodes, similar to 2017-2020. RSV-associated hospitalization rates in 2023-2024 were similar to average 2017-2020 seasonal rates with 5.0 (95% CI, 4.6-5.3) per 1000 among children younger than 5 years; the highest rates were among children aged 0 to 2 months (26.6; 95% CI, 23.0-30.2). Low maternal RSV vaccine uptake precluded assessment of effectiveness. Overall, 10 of 765 case patients (1%) who were RSV positive and 126 of 851 control patients (15%) who were RSV negative received nirsevimab. Nirsevimab effectiveness was 89% (95% CI, 79%-94%) against medically attended RSV-associated ARI and 93% (95% CI, 82%-97%) against RSV-associated hospitalization. Among 229 sequenced specimens, there were no differences in nirsevimab binding site mutations by infant nirsevimab receipt status. CONCLUSIONS AND RELEVANCE: This analysis documented the continued high burden of medically attended RSV-associated ARI among young children in the US. There is a potential for substantial public health impact with increased and equitable prevention product coverage in future seasons.

During 2023, approximately 72,000, or nearly seven in 10, drug overdose deaths in the United States were estimated to involve illegally manufactured fentanyls (IMFs). Carfentanil, a fentanyl analog 100 times more potent than fentanyl, has reemerged in the U.S. drug supply. Using CDC's State Unintentional Drug Overdose Reporting System data, this report describes trends in overdose deaths during January 2021-June 2024, overall and with IMFs detected, by U.S. Census Bureau region, and in deaths with carfentanil detected, in 45 states and the District of Columbia (DC). Numbers of deaths with carfentanil detected by state during January 2023-June 2024 in 49 states and DC are also reported. The number of overdose deaths with IMFs detected declined from 2022 to 2023 in the Northeast (3.2% decline), Midwest (7.8%), and South (2.8%) regions; deaths in the West increased 33.9%. The percentage of deaths with IMFs detected was steady at approximately 70%-80% in the Northeast, Midwest, and South. In contrast, the percentage of deaths with IMFs detected in the West increased from 48.5% during January-March 2021 to 66.5% during April-June 2024. Overdose deaths with carfentanil detected increased approximately sevenfold, from 29 during January-June 2023 to 238 during January-June 2024; during January 2023-June 2024, overdose deaths with carfentanil detected were reported in 37 states. Overdose prevention efforts that address the widespread presence of IMFs, including carfentanil, and can rapidly adapt to other potent opioids in the drug supply might result in lasting reductions in overdose deaths across the entire United States.

Timely initiation of antiretroviral therapy (ART) remains a major challenge in the effort to treat children living with HIV ("CLH") and little is known regarding the dynamics of immune normalization following ART in CLH with varying times to and durations of ART. Here, we leveraged two cohorts of virally-suppressed CLH from Nairobi, Kenya to examine differences in the peripheral immune systems between two cohorts of age-matched children (to control for immune changes with age): one group which initiated ART during early HIV infection and had been on ART for 5-6 years at evaluation (early, long-term treated; "ELT" cohort), and one group which initiated ART later and had been on ART for approximately 9 months at evaluation (delayed, short-term treated; "DST" cohort). We profiled PBMC and purified NK cells from these two cohorts by mass cytometry time-of-flight (CyTOF). Although both groups of CLH had undetectable viral RNA load at evaluation, there were marked differences in both immune composition and immune phenotype between the ELT cohort and the DST cohort. DST donors had reduced CD4 T cell percentages, decreased naive to effector memory T cell ratios, and markedly higher expression of stress-induced markers. Conversely, ELT donors had higher naive to effector memory T cell ratios, low expression of stress-induced markers, and increased expression of markers associated with an effective antiviral response and resolution of inflammation. Collectively, our results demonstrate key differences in the immune systems of virally-suppressed CLH with different ages at ART initiation and durations of treatment and provide further rationale for emphasizing early onset of ART.

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.

Mumps virus (MuV) is a highly contagious paramyxovirus that is endemic in most regions of the world and continues to cause outbreaks even in highly immunized populations. Outbreaks of mumps in countries with high measles, mumps, and rubella vaccination coverage have been attributed to waning immunity and antigenic differences between the Jeryl Lynn vaccine strain (genotype A) and circulating wild-type viruses. To obtain a subunit vaccine, we used structure-based design to engineer the mumps fusion (F) glycoprotein stabilized in its prefusion conformation (Pre-F) as well as a chimeric immunogen comprising Pre-F linked to mumps hemagglutinin neuraminidase (HN); in mice, both Pre-F antigen and the chimeric antigen elicited potent cross-reactive plaque reducing neutralizing titers to genotypes A, G, and H mumps. A crystal structure of mumps Pre-F at 2.16 Å resolution validated the stabilization strategy, while a post-fusion form of F was engineered as a comparator. Monoclonal antibodies to mumps Pre-F and HN were isolated from immunized mice; 7 of 14 Pre-F-specific antibodies and 9 of 15 HN-specific antibodies were capable of neutralizing genotype G MuV with a range of potencies. Additionally, 7 of 14 Pre-F-specific antibodies neutralized genotype A mumps. Structural and binding analyses of Pre-F-specific antibodies revealed binding to four discrete neutralizing antigenic sites and binding analyses of HN-specific antibodies revealed binding to five discrete neutralizing antigenic sites. Overall, the PreF and the chimeric Pre-F/HN immunogens are promising candidates to boost MMR-elicited immunity to mumps or as a next-generation vaccine.

BACKGROUND: The COVID-19 pandemic raised unprecedented challenges to vaccinating children. This multi-center study aimed to compare on-time vaccination of children before and during the COVID-19 pandemic and identify key factors associated with on-time vaccination. METHODS: This study was conducted among children aged 0-6 years enrolled in the New Vaccine Surveillance Network at seven geographically diverse U.S. academic medical centers. Children with acute respiratory illness or acute gastroenteritis were enrolled from emergency department and inpatient settings; healthy control subjects were enrolled from primary care practices. Vaccination data were collected and verified from patient medical records, immunization information systems, and/or provider documentation. On-time vaccination according to Advisory Committee on Immunization Practices recommendations was compared between pre-pandemic (December 2018-February 2020) and pandemic (March 2020-August 2021) periods using bivariate and multivariable analyses, adjusting for key demographic, clinical, and study characteristics. RESULTS: A total of 24,713 children were included in the analytic sample (non-Hispanic 73.4 %; White 51.0 %; publicly insured 69.0 %). On-time vaccination declined between the pre-pandemic (67.3 %) and pandemic (65.4 %) periods (Adjusted Odds Ratio 0.89, 95 % CI 0.84-0.95). The largest declines were observed among children who were < 12 months, male, Black, publicly insured, or whose mothers had a high school-equivalent education or less. The pandemic impact also varied by vaccine type and study site. CONCLUSIONS: This multi-center study revealed a relatively modest overall reduction in on-time vaccination, which may reflect multilevel efforts to address pandemic-associated challenges. However, some patient subgroups and sites experienced greater reductions in on-time vaccination, highlighting the importance of tailoring interventions to increase equitable vaccine delivery, access, and acceptance across populations and communities.

BACKGROUND: Previous investigations into clinical signs and symptoms associated with influenza types and subtypes have not definitively established differences in the clinical presentation or severity of influenza disease. METHODS: The study population included children 0 through 17 years old enrolled at 8 New Vaccine Surveillance Network sites between 2015 and 2020 who tested positive for influenza virus by molecular testing. Demographic and clinical data were collected for study participants via parent/guardian interview and medical chart review. Descriptive statistics were used to summarize demographic and clinical characteristics by influenza subtype. Multivariable logistic regression and Cox proportional hazard models were used to assess effects of age, sex, influenza subtype, and history of asthma on severity, including hospital admission, need for supplemental oxygen, and length of stay. RESULTS: Retractions, cyanosis, and need for supplemental oxygen were more frequently observed among patients with influenza A(H1N1)pdm09. Headaches and sore throat were more commonly reported among patients with influenza B. Children with influenza A(H1N1)pdm09 and children with asthma had significantly increased odds of hospital admission (adjusted odds ratio (AOR): 1.39, 95% CI: 1.14-1.69 and AOR: 2.14, 95% CI: 1.72-2.67, respectively). During admission, children with influenza A(H1N1)pdm09 had significantly increased use of supplemental oxygen compared to children with A(H3N2) (AOR: 0.60, 95% CI: 0.44-0.82) or B (AOR: 0.56, 95% CI: 0.41-0.76). CONCLUSIONS: Among children presenting to the emergency department and admitted to the hospital, influenza A(H1N1)pdm09 caused more severe disease compared to influenza A(H3N2) and influenza B. Asthma also contributed to severe influenza disease regardless of subtype.

BACKGROUND: Rotavirus was the leading cause of acute gastroenteritis among US children until vaccine introduction in 2006, after which, substantial declines in severe rotavirus disease occurred. We evaluated rotavirus vaccine effectiveness (VE) over 13 years (2009-2022). METHODS: We analyzed data from the New Vaccine Surveillance Network using a test-negative case-control design to estimate rotavirus VE against laboratory-confirmed rotavirus infections among children seeking care for acute gastroenteritis (≥3 diarrhea or ≥1 vomiting episodes within 24 hours) in the emergency department (ED) or hospital. Case-patients and control-patients were children whose stool specimens tested rotavirus positive or negative, respectively, by enzyme immunoassay or polymerase chain reaction assays. VE was calculated as (1-adjusted odds ratio)×100%. Adjusted odds ratios were calculated by multivariable unconditional logistic regression. RESULTS: Among 16 188 enrolled children age 8 to 59 months, 1720 (11%) tested positive for rotavirus. Case-patients were less often vaccinated against rotavirus than control-patients (62% versus 88%). VE for receiving ≥1 dose against rotavirus-associated ED visits or hospitalization was 78% (95% confidence interval [CI] 75%-80%). Stratifying by a modified Vesikari Severity Score, VE was 59% (95% CI 49%-67%), 80% (95% CI 77%-83%), and 94% (95% CI 90%-97%) against mild, moderately severe, and very severe disease, respectively. Rotavirus vaccines conferred protection against common circulating genotypes (G1P[8], G2P[4], G3P[8], G9P[8], and G12[P8]). VE was higher in children <3 years (73% to 88%); protection decreased as age increased. CONCLUSIONS: Rotavirus vaccines remain highly effective in preventing ED visits and hospitalizations in US children.

A modified Vesikari severity score (MVSS) is a useful research tool for assessing severity of acute gastroenteritis. We present a MVSS for studies in which a follow-up assessment of symptoms cannot be obtained. The MVSS significantly correlated with other markers of severity, including illness duration and work and school absenteeism.

Influenza C virus (ICV) is an orthomyxovirus related to influenza A and B, yet due to few commercial assays, epidemiologic studies may underestimate incidence of ICV infection and disease. We describe the epidemiology and characteristics of ICV within the New Vaccine Surveillance Network (NVSN), a Centers for Disease Control and Prevention (CDC)-led network that conducts population-based surveillance for pediatric acute respiratory illness (ARI). Nasal or/combined throat swabs were collected from emergency department (ED) or inpatient ARI cases, or healthy controls, between 12/05/2016-10/31/2019 and tested by molecular assays for ICV and other respiratory viruses. Parent surveys and chart review were used to analyze demographic and clinical characteristics of ICV+ children. Among 19,321 children tested for ICV, 115/17,668 (0.7 %) ARI cases and 8/1653 (0.5 %) healthy controls tested ICV+. Median age of ICV+ patients was 18 months and 88 (71.5 %) were ≤36 months. Among ICV+ ARI patients, 40 % (46/115) were enrolled in the ED, 60 % (69/115) were inpatients, with 15 admitted to intensive care. Most ICV+ ARI patients had fever (67.8 %), cough (94.8 %), or wheezing (60.9 %). Most (60.9 %) ARI cases had ≥1 co-detected viruses including rhinovirus, RSV, and adenovirus. In summary, ICV detection was rarely associated with ARI in children, and most ICV+ patients were ≤3 years old with co-detected respiratory viruses.

Background: Bilateral oophorectomy has been linked to numerous health outcomes, some of which can have a long latency period. Limited data are available on bilateral oophorectomy prevalence among U.S. women. Methods: The National Health Interview Survey fielded measures of bilateral oophorectomy most recently in 2010 and 2015. We pooled these 2 data years to present bilateral oophorectomy prevalence estimates by age-group, race, ethnicity, geographic region, and hysterectomy status. Results: Our study found bilateral oophorectomy was common among older women. Among women aged 70-79 years, 29% reported a bilateral oophorectomy, compared with <1% for women aged 20-29 years. By geographic region, bilateral oophorectomy prevalence among women 20-84 years was 12.3% in the South, 10.8% in the Midwest, 9.4% in the West, and 8.0% in the Northeast. Small numbers limited our ability to generate age-specific estimates for American Indian and Alaska Native women and subgroups of Asian and Hispanic women. Nearly half of women who had a bilateral oophorectomy reported their procedure occurred more than 20 years ago. Among women aged 20-84 years who reported a hysterectomy, 57% reported they also had both of their ovaries removed. Conclusion: Standard measures of incidence rates for ovarian cancer are not adjusted for oophorectomy status. These findings suggest that ovarian cancer incidence rates may be underestimated among older women. Continued monitoring of bilateral oophorectomy prevalence will be needed to track its potential impact on ovarian cancer incidence and numerous other chronic health outcomes.

BACKGROUND: Exclusive breastfeeding (EBF) in the first six months remains low globally, despite known benefits of lower morbidity and mortality among breastfed infants. It is important to understand factors associated with breastfeeding to support optimal breastfeeding practices, particularly in settings with a high burden of HIV. METHODS: We analyzed data from a population-level survey of mother-infant pairs attending 6-week or 9-month immunizations at 141 clinics across Kenya. Primary outcomes included maternal report of (1) EBF at 6-week visit, defined as currently feeding the infant breast milk only, (2) EBF for the first 6-months of life, defined as breastfeeding or feeding the infant breast milk only with no introduction of other liquids or solid foods until 6 months, and (3) continued breastfeeding with complementary feeding at 9-months. Correlates of breastfeeding practices were assessed using generalized Poisson regression models accounting for facility-level clustering. RESULTS: Among 1662 mothers at 6-weeks, nearly all self-reported breastfeeding of whom 93% were EBF. Among 1180 mothers at 9-months, 99% had ever breastfed, 94% were currently breastfeeding and 73% reported 6-month EBF. At 6-weeks, younger age (< 25 years) (adjusted Prevalence Ratio (aPR) 0.96; 95% CI 0.93, 0.99), lower education (aPR 0.96; 95% CI 0.93, 0.99) and recent infant illness (aPR 0.97; 95% CI 0.94, 1.00) were associated with lower EBF prevalence while women living with HIV (WLWH) had higher EBF prevalence (aPR 1.06; 95% CI 1.02, 1.10) than women without HIV. 6-month EBF prevalence was 26% higher in WLWH (aPR 1.26; 95% CI 1.15, 1.35) than women without HIV, 14% lower in women reporting mild or above depressive symptoms (aPR 0.86; 95% CI 0.76, 0.99) than those with none or minimal depressive symptoms, and 15% lower in women with versus without history of intimate partner violence (aPR 0.85; 95% CI 0.74, 0.98). At 9-months, WLWH had a lower prevalence of continued breastfeeding with complementary feeding (aPR 0.73; 95% CI 0.64, 0.84) than women without HIV. CONCLUSION: WLWH had higher EBF prevalence in the first 6-months, but lower prevalence of continued breastfeeding at 9-months. Strategies to support EBF and continued breastfeeding beyond 6-months postpartum, particularly among WLWH, are needed.

COVID-19, caused by the SARS-CoV-2 virus, is a highly pathogenic emerging infectious disease. Healthcare personnel (HCP) are presumably at higher risk of acquiring emerging infections because of occupational exposure. The prevalence of COVID-19 in HCP is unknown, particularly in low- to middle-income countries like El Salvador. The goal of this study was to determine the seroprevalence of anti-SARS-CoV-2 antibodies among HCP in El Salvador just prior to vaccine rollout in March 2021. We evaluated 2176 participants from a nationally representative sample of national healthcare institutions. We found 40.4% (n = 880) of the study participants were seropositive for anti-spike protein antibodies. Significant factors associated with infection included younger age; living within the central, more populated zone of the country; living in a larger household (≥7 members); household members with COVID-19 or compatible symptoms; and those who worked in auxiliary services (i.e., housekeeping and food services). These findings provide insight into opportunities to mitigate SARS-CoV-2 risk and other emerging respiratory pathogens in HCP in El Salvador.

BACKGROUND: The coronavirus disease 2019 pandemic disrupted respiratory syncytial virus (RSV) seasonality resulting in early, atypical RSV seasons in 2021 and 2022, with an intense 2022 peak overwhelming many pediatric healthcare facilities. METHODS: We conducted prospective surveillance for acute respiratory illness during 2016-2022 at 7 pediatric hospitals. We interviewed parents, reviewed medical records, and tested respiratory specimens for RSV and other respiratory viruses. We estimated annual RSV-associated hospitalization rates in children aged <5 years and compared hospitalization rates and characteristics of RSV-positive hospitalized children over 4 prepandemic seasons (2016-2020) to those hospitalized in 2021 or 2022. RESULTS: There was no difference in median age or age distribution between prepandemic and 2021 seasons. Median age of children hospitalized with RSV was higher in 2022 (9.6 months vs 6.0 months, P < .001). RSV-associated hospitalization rates were higher in 2021 and 2022 than the prepandemic average across age groups. Comparing 2021 to 2022, RSV-associated hospitalization rates were similar among children <2 years of age; however, children aged 24 to 59 months had significantly higher rates of RSV-associated hospitalization in 2022 (rate ratio 1.68 [95% confidence interval 1.37-2.00]). More RSV-positive hospitalized children received supplemental oxygen and there were more respiratory virus codetections in 2022 than in prepandemic seasons (P < .001 and P = .003, respectively), but there was no difference in the proportion hypoxemic, mechanically ventilated, or admitted to intensive care. CONCLUSIONS: The atypical 2021 and 2022 RSV seasons resulted in higher hospitalization rates with similar disease severity to prepandemic seasons.

BACKGROUND: Respiratory syncytial virus (RSV) is a leading cause of acute respiratory illnesses in children. RSV can be broadly categorized into 2 major subtypes: A and B. RSV subtypes have been known to cocirculate with variability in different regions of the world. Clinical associations with viral subtype have been studied among children with conflicting findings such that no conclusive relationships between RSV subtype and severity have been established. METHODS: During 2016-2020, children aged <5 years were enrolled in prospective surveillance in the emergency department or inpatient settings at 7 US pediatric medical centers. Surveillance data collection included parent/guardian interviews, chart reviews, and collection of midturbinate nasal plus/minus throat swabs for RSV (RSV-A, RSV-B, and untyped) using reverse transcription polymerase chain reaction. RESULTS: Among 6398 RSV-positive children aged <5 years, 3424 (54%) had subtype RSV-A infections, 2602 (41%) had subtype RSV-B infections, and 272 (5%) were not typed, inconclusive, or mixed infections. In both adjusted and unadjusted analyses, RSV-A-positive children were more likely to be hospitalized, as well as when restricted to <1 year. By season, RSV-A and RSV-B cocirculated in varying levels, with 1 subtype dominating proportionally. CONCLUSIONS: Findings indicate that RSV-A and RSV-B may only be marginally clinically distinguishable, but both subtypes are associated with medically attended illness in children aged <5 years. Furthermore, circulation of RSV subtypes varies substantially each year, seasonally and geographically. With introduction of new RSV prevention products, this highlights the importance of continued monitoring of RSV-A and RSV-B subtypes.