Background: Most epidemiologic studies and clinical testing use single nasal/nasopharyngeal swab (NPS) for respiratory syncytial virus (RSV) detection. Studies document that RSV detection improves if another specimen is added to NPS, but the impact of using multiple specimen types has not been assessed. We quantified RSV detection increase using multiple-specimen testing versus NPS alone. Methods: Hospitalized adults aged ≥40 years with acute respiratory illness were prospectively enrolled in 7 US/Canadian hospitals. NPS, saliva, sputa, and acute/convalescent sera were collected and tested. Results: Among 3669 participants, 100% had NPS, 97.7% saliva, 33.0% sputum, and 33.4% paired serology. RSV detection was 112% higher (95% CI, 86%–141%) using all specimen types as compared with NPS alone. Serology test sensitivity was the highest (73.0%; 95% CI, 65.1%–80.8%), followed by sputum (70.1%; 95% CI, 62.1%–78.0%), saliva (61.4%; 95% CI, 55.4%–67.5%), and NPS (47.2%; 95% CI, 41.1%–53.4%). Among those with congestive heart failure exacerbations, additional specimens increased detection by 267% (95% CI, 85%–625%), and saliva detected more infections than NPS. Among 1013 participants with paired NPSs from different time points, specimens collected on average 1 day later detected 30% fewer RSV infections. Conclusions: RSV detection increased >100% using 4 specimen types, suggesting a 2-fold correction factor is appropriate for incidence and prevalence studies relying on NPS alone. Saliva was more sensitive than NPS, warranting further study, particularly in cardiac cases.

Background: Respiratory syncytial virus (RSV) is an important cause of severe respiratory illness among older adults. Previously, we showed that the RSVpreF vaccine (Abrysvo; Pfizer) prevents RSV-related lower respiratory tract disease–related emergency department (ED) visits/hospitalizations in older adults. Here, we evaluate its effectiveness against additional acute respiratory illness (ARI) end points, including severe disease, among high-risk persons. Methods: This was a retrospective test-negative case-control study of adults aged ≥60 years at Kaiser Permanente Southern California with ARI ED visits/hospitalizations, defined by International Classification of Diseases, Tenth Revision discharge code, from 24 November 2023 to 9 April 2024. Case patients tested positive for RSV. Controls in the primary analysis tested negative for RSV, human metapneumovirus, influenza, and severe acute respiratory syndrome coronavirus 2 and positive for a non–vaccine-preventable pathogen. The exposure was RSVpreF receipt ≥21 days before ARI diagnosis. Vaccine effectiveness (VE) was calculated from adjusted odds ratios via multivariable logistic regression. Results: Overall, 8965 ARI ED visits/hospitalizations with RSV testing were included; 7.8% of patients were RSV positive, among whom 0.3% had received RSVpreF, compared with 3.6% of controls. The adjusted VE was 92% (95% confidence interval, 64%–98%). We estimated similar VE among patients with risk conditions (92% [95% confidence interval: 65%–98%]), the oldest subgroup (age ≥75 years; 95% [60%–99%]), those with critical outcomes (intensive care unit admission, mechanical ventilation, respiratory failure, vasopressor use, or death; 90% [16%–99%]), and those with severe disease (defined as ED visit or hospitalization requiring oxygen; 92% [35%–99%]). Conclusions: Among older adults, RSVpreF demonstrated high VE against RSV-related ARI hospitalization or ED visits, including among high-risk subgroups, and against severe outcomes. RSV vaccination programs can protect groups at the highest risk of severe disease.

Since RSV vaccine licensure in 2023, vaccine effectiveness (VE) studies demonstrated first season protection against severe RSV disease including RSV-related hospitalization/emergency department (ED) visits. Here, we estimate VE over two seasons, by RSV subtype, and for additional high-risk subgroups. This retrospective test-negative case–control study included adults ≥60 years at Kaiser Permanente Southern California with lower respiratory tract disease (LRTD) or acute respiratory illness (ARI) hospitalization/ED during 24 November 2023─09 April 2024 and 05 November 2024─26 April 2025. In primary analyses, cases were RSV-positive and controls were negative for: RSV, SARS-CoV-2, influenza, and positive for a non-vaccine-preventable pathogen. Exposure was bivalent RSVpreF receipt ≥21 days before LRTD/ARI. VE was calculated using adjusted odds ratios from multivariable logistic regression. “First season after vaccination” includes events in the same RSV season as vaccination; “second season” includes events in 2024–25 among those vaccinated in 2023–24. VE against RSV-associated LRTD hospitalizations/ED was 81% (95% CI: 68–89) and 76% (95% CI: 48–89) for first and second seasons after vaccination, respectively. Limiting to those vaccinated in 2023/2024, VE was 87% (95% CI: 37–97) 0–<6 and 77% (95% CI: 54–89) 6–18 months post-vaccination. Protection persisted across both seasons for adults aged ≥75 years, those with risk factors, frailty, immunocompromise, and by RSV A/B. VE in immunocompromised adults appeared to decrease more quickly: 74% (95% CI: 37–89) first season to 54% (95% CI: −48 to 85) second season. RSVpreF vaccination was associated with protection against RSV-associated severe respiratory illness, overall and among the most vulnerable patients. VE appeared to decline modestly across two seasons in most populations, this finding was more pronounced among immunocompromised adults. Our VE estimates indicate potentially substantial public health benefit of RSV vaccination. This was a Pfizer-sponsored study.

Background and Aims: It is not known whether the bivalent respiratory syncytial virus prefusion F protein-based (RSVpreF) vaccine reduces outcomes in individuals with atherosclerotic cardiovascular disease (ASCVD). The aim was to evaluate the vaccine effectiveness (VE) of an RSVpreF vaccine vs no vaccine on respiratory and cardiovascular outcomes in persons with or without pre-existing ASCVD. Methods: We conducted a prespecified secondary analysis of the DAN-RSV trial. Adults aged ≥60 years were randomized 1:1 to RSVpreF vaccine or no vaccine. Baseline and outcome data were collected through nationwide registries. The primary outcome was respiratory syncytial virus-related respiratory tract disease hospitalization. The principal major adverse cardiovascular event outcome was a composite of hospitalization for myocardial infarction, stroke, or heart failure. Heterogeneity in VE was assessed among participants with and without ASCVD. Results: The incidence rate of almost all outcomes was higher in participants with pre-existing ASCVD (n = 14 241) vs those without (n = 117 035). Vaccine effectiveness was generally consistent by ASCVD status (Pinteraction ≥ .05 for all but one interaction). Among persons without and with ASCVD, VE for the primary outcome was 80.0% [95% confidence interval (CI), 29.3–96.3] vs 100.0% (95% CI, −141.3 to 100.0), respectively (Pinteraction > .99). Vaccine effectiveness for major adverse cardiovascular events was 9.3% (95% CI, −15.1 to 28.6) in participants without, and 12.0% (95% CI, −34.6 to 43.3) in participants with, pre-existing ASCVD (Pinteraction = .90). Conclusions: The VE of an RSVpreF vaccine vs no vaccine against respiratory and cardiovascular outcomes was similar among individuals ≥ 60 years of age with pre-existing ASCVD as compared with those without.

: Rotavirus is responsible for 26% of diarrheal deaths in Latin America and the Caribbean. Haiti introduced the monovalent rotavirus vaccine in April 2014. The objective of this analysis is to describe the impact of the rotavirus vaccine on hospitalizations among Haitian children younger than 5 years old during the first 5 years after introduction. This analysis includes all children with diarrhea who were enrolled as part of a sentinel surveillance system at two hospitals from May 2013 to April 2019. We compare the proportion of rotavirus-positive specimens in each post-vaccine introduction year to the pre-vaccine period. To account for the potential dilution of the proportion of rotavirus-positive specimens from a waning cholera outbreak, we also analyzed annual trends in the absolute number of positive stools, fit a two-component finite-mixture model to the negative specimens, and fit a negative binomial time series model to the pre-vaccine rotavirus-positive specimens to predict the number of rotavirus diarrhea hospital admissions in the absence of rotavirus vaccination. The overall percentage of rotavirus-positive specimens declined by 22% the first year after introduction, increased by 17% the second year, and declined by 33% to 50% the subsequent 3 years. All sensitivity analyses confirmed an overall decline. We observed a clear annual rotavirus seasonality before and after vaccine introduction, with the greatest activity in December through April, and a biennial pattern, with high sharp peaks and flatter longer periods of increased rotavirus activity in alternating years, consistent with suboptimal vaccination coverage. Overall, our study shows evidence that the introduction of the rotavirus vaccine reduced the burden of severe rotavirus diarrhea.