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Maternal Vaccine Receipt and Infant Hospital and Emergency Visits for Influenza and Pertussis
This population-based cohort study used the health care utilization databases from the Lombardy region of Italy. Pregnant individuals who received the influenza and Tdap vaccine among all live-birth pregnancies in 2018 to 2022 were included. Each vaccinated mother was matched with a nonvaccinated counterpart based on month and year of delivery, gestational age at birth, and pregnancy multiplicity. Analyses were performed from April 2024 to February 2025. The primary outcomes were infant hospitalizations or ED visits due to influenza and pertussis. This study included 53,448 pregnant individuals who received the Tdap vaccine and 5,347 who received influenza vaccine.
Infants born to mothers who received the Tdap vaccine had a lower risk of hospitalization or ED visit for pertussis (VE, 88.6%). Infants born to mothers who received the influenza vaccine had a lower risk of hospitalization or ED visit for influenza (VE, 69.7%).
Impact of Universal Nirsevimab Prophylaxis in Infants on Hospital and Primary Care Outcomes Across Two Respiratory Syncytial Virus Seasons in Galicia, Spain (NIRSE-GAL): A Population-based Prospective Observational Study
Study they included all infants eligible for nirsevimab in the 2023–24 RSV campaign in Galicia, followed up from their first RSV season (2023–24) until the end of their second RSV season (2024–25). The primary endpoint was RSV-related lower respiratory tract infection (LRTI) hospitalisation. They also looked at a number of secondary endpoints. The first recurrences of these endpoints were also assessed as secondary endpoints. Impact was estimated and adjusted for RSV seasonality, and evaluated across three follow-up periods: The first RSV season, the second RSV season, and up to 18 months. Of 12,492 eligible infants, 11,796 received nirsevimab (94·4% coverage). Compared with historical cohorts, RSV-related LRTI hospitalisations decreased by 85·9% (95% CI 80·2–90·0) in the first season and 55·3% (22·5–74·3) in the second, with an estimated 123 infants needing to be immunised to prevent a second-season admission.
Interim Safety of RSVpreF Vaccination During Pregnancy
The analysis, led by Harvard Medical School researchers and including authors from Pfizer, draws on data from five U.S. health plans on 54,011 pregnancies during the first full RSV season following Abrysvo’s approval (September 2023 to June 2024). Of all participants, 19% received the Abrysvo vaccine from 32 to 36 weeks’ gestation. The team found no statistically significant increase in preterm birth, hypertensive (high blood pressure) disorders, premature rupture of membranes (PROM), or preterm PROM among vaccinated women. Safety monitoring is ongoing. “Continual safety monitoring is crucial,” write the authors, who will issue a final safety report in 2029 that will assess more outcomes, include underrepresented populations, and analyze different subgroups.
Evaluating the Effectiveness of 2024–2025 Seasonal mRNA-1273 Vaccination Against COVID-19-Related Hospitalizations and Medically Attended COVID-19 Among Adults Aged ≥ 18 years in the United States: An Observational Matched Cohort Study
These results come from a retrospective matched cohort study where 596,248 mRNA-1273 KP.2 vaccine recipients were matched 1:1 to unvaccinated adults. The mean (standard deviation) age was 63 (17) years, with more than half of the population being 65 years or older. Approximately 70% of individuals had an underlying medical condition making them high-risk for severe outcomes for COVID-19. VE was 52.8% against COVID-19-related hospitalization and 39.4% against medically-attended COVID-19 over a median follow-up of 55 days in an interim analysis. The VE was sustained throughout the entire study period and shown to be 45.2% against COVID-19-related hospitalizations and 33.1% against medically-attended COVID-19 over a median follow-up of 127 days.
Incidence and Severity of Postacute Sequelae of SARS-CoV-2 Infection in the Omicron Era: A Prospective Cohort Study
In a prospective cohort study of 2,960 non-hospitalized adults with acute SARS-CoV-2 infection, older age, female sex, rural residence, high BMI, greater acute infection severity, chronic lung disease, and poorer general health at baseline were associated with higher risk and severity of postacute sequelae. Recent vaccination was associated with lower postacute sequelae risk and severity, while antiviral therapy was not.
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