Sarah N. Cox

Background: Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract disease in infants, with the highest burden in the first 6 months of life. Maternal immunization with the bivalent (RSV-A and RSV-B) prefusion F (RSVPreF) protein subunit vaccine (ABRYSVO) is a recently recommended strategy for preventing RSV-related outcomes in infants. First licensed for use in pregnancy in 2023, the RSVPreF vaccine demonstrated efficacy in a single pivotal randomized trial (Maternal Immunization Study for Safety and Efficacy; MATISSE); postlicensure real-world evidence on vaccine effectiveness across settings, seasons, and subgroups and on antibody durability and transplacental transfer remains limited and has not been synthesized in a continuously updated framework, motivating this review. Objective: This living systematic review and meta-analysis will synthesize emerging postlicensure data on the efficacy, effectiveness, and immunogenicity of the RSVPreF vaccine in real-world settings. Methods: We will conduct, in real time, a living systematic review and meta-analysis following Cochrane methods and PRISMA-P (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols) guidance, including randomized clinical trials and postlicensure real-world studies (eg, cohort, case-control, test-negative, and quasi-experimental studies). Primary objectives are evaluation of vaccine efficacy and effectiveness in preventing RSV-specific and all-cause respiratory disease and immunogenicity in infants and pregnant individuals. Vaccine effectiveness outcomes include RSV laboratory-confirmed infection, RSV acute respiratory illness, RSV lower respiratory tract disease, RSV hospitalization, RSV complications, all-cause lower respiratory tract disease and hospitalization, and antibiotic use in infants with RSV infection. Immunogenicity outcomes include maternal neutralizing antibody titers, maternal-infant transfer ratios, infant titers over time, and RSV viral load. We will search MEDLINE, Embase, the Cochrane Library, LILACS, Science Citation Index Expanded, Chinese biomedical and citation databases, clinical trial registries from January 2023 onward with no language restrictions, updating at least monthly. Two investigators will independently select studies, extract data, and assess risk of bias. Adjusted estimates will be standardized to vaccine efficacy and effectiveness. Certainty will be graded using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Results: This living systematic review was funded in June 2025. Searches began in January 2023 and will continue with surveillance updates at least monthly until April 2028. As of January 2026, 837 records were screened, 105 (12.5%) were assessed in full text, and 12 (1.4%) met the inclusion criteria, of which 10 (1.2%) contributed extractable data. Data collection and analysis are ongoing and displayed on an interactive dashboard. Findings will be disseminated through peer-reviewed publications, conferences, and a real-time dashboard, with the first effectiveness estimates available in July 2026. Conclusions: This living systematic review and meta-analysis will provide a continuously updated synthesis of real-world evidence on maternal RSVPreF vaccination to inform clinical and policy decisions.

Few studies have characterized immune correlates of SARS-CoV-2 infection risk in children, particularly those with hybrid immunity from vaccination and prior infection. We conduct a prospective community-based cohort study of 1509 U.S. children (2022–2024), performing weekly SARS-CoV-2 PCR testing and measuring baseline binding and neutralizing antibody titers against multiple variants. Higher antibody levels, notably nucleocapsid-binding and Omicron-specific neutralizing antibodies, are significantly associated with reduced risk of SARS-CoV-2 infection after adjusting for age, recent infection, exposure settings, and temporal trends (adjusted hazard ratios ranging from 0.60 to 0.87 per positive unit difference in log₁₀-fold antibody level (AU/mL)). Secondary analyses suggest these findings are robust to multiple stratifications of SARS-CoV-2 immune status, are relevant across different pediatric age groups, and appear to apply to both overall and symptomatic infection risk. Together, the results suggest that specific antibodies can predict relative infection risk in pediatric populations with diverse immune histories. Understanding these immune correlates may inform tailored vaccination strategies and risk assessments as SARS-CoV-2 continues to evolve.

Background: COVID-19 vaccine hesitancy remains a public health issue despite the fact that vaccines are readily available and recommended for all persons aged 5 years or older in the United States. We aimed to describe parental plan to vaccinate their children in two different populations: families in a prospective, longitudinal cohort study and families experiencing homelessness enrolled in cross-sectional surveillance for acute respiratory infections. Methods: Participants were parents/guardians of children aged <18 years, recruited either from a serial cross-sectional homeless study in Seattle-King County, Washington or from a household cohort study in the Seattle Metropolitan area. Participants were surveyed during October 2020-May 2021 about their plans to vaccinate their child against COVID-19. Vaccine plans were described by study population as well as by sociodemographic features and over time. Results: Among parents of 640 children enrolled in the household study surveyed in October 2021, 66% reported planning to vaccinate their child vaccinated against COVID-19 once vaccines became available. This proportion increased slightly over the study period, to 75% in May 2021. In the homeless study, 1284 surveys were collected from parents of 338 children. The proportion of parents of families experiencing homelessness who planned to have their child vaccinated against COVID-19 ranged from 52% in November 2020 to 16% in March 2021. Conclusion: COVID-19 vaccine plan among parents of children experiencing homelessness in Seattle-King County decreased over time, with the majority of parents reporting that they did not plan or were undecided about COVID-19 vaccination for their children by May 2021. Further investigations are needed among families experiencing homelessness to assess vaccine attitudes and perceived barriers to getting their children vaccinated against COVID-19.

Few population-based studies have evaluated the importance of pre-existing respiratory syncytial virus (RSV) antibody on RSV susceptibility among children and adults. We conducted a prospective, community-based cohort study among individuals aged 6 months-50 years in Oregon and Washington State, USA (June 2022-May 2023), with weekly symptom surveys and swab collection regardless of symptoms. Swabs were tested for RSV using RT-qPCR. Enrollment sera were tested for RSV prefusion F IgG binding (all participants) and neutralizing antibodies (pediatric participants). We detected 305 RSV illnesses among 3237 participants from 1188 households. Using proportional hazards regression, higher RSV binding antibody titers were associated with a lower estimated hazard of RSV among pediatric participants (hazard ratio=0.66 per 1-unit difference in log₁₀-RSV antibody titer; 95% CI: 0.56, 0.78). In a post-pandemic period, pre-existing RSV antibody titers were associated with a lower risk of RSV illness in children aged 6 months-17 years, which could inform vaccine development for this age group.

The University of Washington Department of Epidemiology launched a quarterly virtual anti-racism journal club in spring 2020. After two quarters, students expressed concerns that White students dominated discussions. Students and instructors worked together to amplify the voices of Black, Indigenous, and People of Color (BIPOC) students using racial affinity caucuses (RACs) as a pedagogical intervention before classroom discussions. We used the Consolidated Framework for Implementation Research (CFIR) to examine intervention process and determinants as described by students via anonymous course evaluations and the Public Health Critical Race Praxis (PHCRP) to identify “how is racism operating here?” across CFIR domains. On a scale of zero to five (0: Very Poor, 5: Excellent), the overall course effectiveness was rated just below “Excellent” (average: 4.8), while the effectiveness of RACs was rated just below “Very Good” (average: 3.7). Student comments endorsed the RAC intervention as a CFIR innovation that effectively supported BIPOC students while acknowledging the barriers and facilitators of its implementation. Student and instructor flexibility, humility, courage to engage in praxis, and willingness to learn from failure were essential to implementation. Yet, students rated the course and RAC intervention highly, suggesting that anti-racism praxis can foster classroom learning in an epidemiology classroom.

Background: Household transmission of respiratory viruses may drive community spread. Few recent studies have examined household respiratory syncytial virus (RSV) transmission in the United States. Methods: We conducted a prospective community-based cohort study from 1 June 2022 to 31 May 2023. Participants had blood samples collected and completed nasal swabs and surveys at least weekly, irrespective of symptoms. We tested serum for RSV antibody, nasal swabs by quantitative reverse transcription polymerase chain reaction (RT-qPCR), and performed whole genome sequencing. We evaluated secondary RSV transmission and associated risk factors based on a log-linear Poisson regression model. Results: RSV was detected among 310 (10%) participants within 200 (20%) households. Most (94%) index cases were symptomatic. We identified 37 cases of potential secondary transmission within 14 days of a distinct index case (10%, 95% confidence interval [CI]: 7%, 14%); median age of index and secondary cases were 6 (interquartile range [IQR]: 3–10) and 35 (7–41) years, respectively, with 89% (24/27) of index cases aged 6 months to 12 years. Factors associated with increased risk of RSV transmission included index case viral detection ≥1 week and contact age ≤12 years. Of 120 sequenced specimens, the main lineages represented were A.d.5.2 (n = 37) and A.d.1 (n = 30). Sequenced viruses from households with ≥2 RSV infections were similar when occurring within ≤14 days (mean pairwise difference 4 [range 0–13], n = 17 households), compared to those >14 days (137 [37–236], n = 2). Conclusions: Most RSV household transmission occurs from infants and young children to adults. Viral genome sequencing demonstrated that multiple household infections within a 14-day period are likely due to within-household transmission.

Introduction: Oral pre-exposure prophylaxis (PrEP) is a priority intervention for scale-up in countries with high HIV prevalence. Policymakers must decide how to optimise PrEP allocation to maximise health benefits within limited budgets. We assessed the health and economic impact of PrEP scale-up among different subgroups and regions in western Kenya. Methods: We adapted an agent-based network model, EMOD-HIV, to simulate PrEP uptake in six counties of western Kenya across seven subgroups including serodiscordant couples (SDCs), adolescent girls and young women (AGYW), adolescent boys and young men, women with multiple partners and men with multiple partners. We modelled 5 years of PrEP provision assuming 90% PrEP uptake in the prioritised subgroups and evaluated outcomes over 20 years compared with a no PrEP scenario. All results are presented in 2021 USD$. Results: Population PrEP coverage was highest in the broad AGYW scenario (8.3%, ~2 fold higher than the next highest coverage scenario) and lowest in the SDC scenario (0.37%). Across scenarios, PrEP averted 4.5%–21.3% of infections over the 5-year implementation. PrEP provision to SDCs was associated with the lowest incremental cost-effectiveness ratio (ICER), $245 per disability-adjusted life year (DALY) averted (CI $179 to $435), followed by women and men with multiple partners ($1898 (CI $1002 to $6771) and $2351 (CI $1 831 to $3494) per DALY averted, respectively). Targeted strategies were more efficient than broad provision even in high HIV prevalence counties; PrEP scale-up for AGYW with multiple partners had an ICER per DALY averted of $4745 (CI $2059 to $22 515) compared with $12 351 for broad AGYW (CI $7 050 to $33,955). In general, ICERs were lower in counties with higher HIV prevalence. Conclusions: PrEP scale-up can avert substantial HIV infections and increasing PrEP demand for subgroups at higher risk can increase efficiency of PrEP programmes. Our results on health and cost impact of PrEP across geographic regions in western Kenya can be used for budgetary planning and priority setting.

Surveillance of enteroviruses in congregate settings may enable early detection and prompt implementation of outbreak control measures.