The BNT162b2 mRNA vaccine (Pfizer-BioNTech) was the first SARS-CoV-2 vaccine authorized and the most widely used in older persons in France. Although no increases in cardiovascular events were reported in phase 3 trials,¹ questions emerged once the vaccine was used on a large scale because older people were underrepresented in the trials. We evaluated the short-term risk of severe cardiovascular events among French people aged 75 years or older after the administration of the BNT162b2 mRNA vaccine.

Cases of myocarditis and pericarditis have been reported following the receipt of Covid-19 mRNA vaccines. As vaccination campaigns are still to be extended, we aimed to provide a comprehensive assessment of the association, by vaccine and across sex and age groups. Using nationwide hospital discharge and vaccine data, we analysed all 1612 cases of myocarditis and 1613 cases of pericarditis that occurred in France in the period from May 12, 2021 to October 31, 2021. We perform matched case-control studies and find increased risks of myocarditis and pericarditis during the first week following vaccination, and particularly after the second dose, with adjusted odds ratios of myocarditis of 8.1 (95% confidence interval [CI], 6.7 to 9.9) for the BNT162b2 and 30 (95% CI, 21 to 43) for the mRNA-1273 vaccine. The largest associations are observed for myocarditis following mRNA-1273 vaccination in persons aged 18 to 24 years. Estimates of excess cases attributable to vaccination also reveal a substantial burden of both myocarditis and pericarditis across other age groups and in both males and females.

Severe cardiovascular events (myocardial infarction [MI], pulmonary embolism [PE], and stroke) have been reported after COVID-19 vaccination. In this French registry-based analysis of adults younge... Visual Risk for MI, Stroke, and PE Following COVID-19 Vaccines. Severe cardiovascular events (myocardial infarction [MI], pulmonary embolism [PE], and stroke) have been reported after COVI... Background: The BNT162b2 (Pfizer–BioNTech) vaccine has been shown to be safe with regard to risk for severe cardiovascular events (such as myocardial infarction [MI], pulmonary embolism [PE], and s...

In pivotal trials, nirsevimab showed promising efficacy in reducing hospitalizations for respiratory syncytial virus-associated lower respiratory tract infections (RSV-LRTIs). Nirsevimab's real-world effectiveness needs to be assessed. This population-based study used the French National Health Data System. All infants born between February 6 and September 15, 2023 were eligible. Each day during the study period (September 15, 2023, to January 31, 2024), all infants newly passively immunized with nirsevimab were matched to unimmunized controls in a 1:1 ratio according to sex, birth month, gestational age, department of residence, and the French Social Deprivation Index (Fdep). Study outcomes included RSV-LRTI-related hospitalization, RSV-LRTI necessitating admission to a pediatric intensive care unit (PICU) or high dependency unit (HDU), and RSV-LRTI requiring ventilation support or oxygen therapy. We estimated nirsevimab effectiveness using propensity score-weighted conditional Cox models. The study included 82,474 infants (41,237 in each group) with a median follow-up of 118 days (interquartile range, 76 to 125). The population included predominantly male infants (52.5%) born at term (94.6%), mostly between April and July 2023 (64.0%), and from more advantaged municipalities (FDep first quintile: 29.8%). In total, 342 infants (0.8%) in the nirsevimab group and 992 (2.4%) in the unimmunized group were hospitalized for RSV-LRTI. Nirsevimab's effectiveness was 65% (95% confidence interval [CI], 61 to 69) for RSV-LRTI hospitalizations; 74% (95% CI, 56 to 85) for RSV-LRTI PICU admissions; 64% (95% CI, 55 to 71) for RSV-LRTI HDU admissions; 66% (95% CI, 51 to 76) for RSV-LRTI hospitalization requiring ventilation support; and 67% (95% CI, 57 to 75) for RSV-LRTI hospitalization requiring oxygen therapy. Subgroup and sensitivity analyses yielded consistent effectiveness estimates. This study in a nationwide monoclonal antibody infusion setting suggests that a single injection of nirsevimab was associated with substantial protection of infants against hospitalization for RSV-LRTI.

Importance: Respiratory syncytial virus (RSV) is a leading cause of hospitalization in infants. The comparative effectiveness of 2 recently introduced preventive strategies (infant immunization through placental antibody transfer after maternal vaccination with the RSV prefusion F protein [RSVpreF] vaccine and passive infant immunization with nirsevimab) remains unknown. Objective: To compare the associations of maternal vaccination with the RSVpreF vaccine vs passive infant immunization with nirsevimab for the prevention of RSV-related hospitalization. Design, Setting, and Participants: This population-based cohort study used data from the French National Health Data System. Maternal vaccination with the RSVpreF vaccine occurred during 32 to 36 weeks’ gestation among infants born in mainland France between September 1 and December 31, 2024. Passive infant immunization with nirsevimab occurred prior to hospital discharge. Infants were matched 1:1 by maternity ward discharge date, sex, gestational age, and region. Follow-up ended at the time of RSV hospitalization or death or on February 28, 2025. Exposures: Maternal immunization with the RSVpreF vaccine and passive infant immunization with nirsevimab. Main Outcomes and Measures: The primary outcome was hospitalization for RSV-associated lower respiratory tract infection. The secondary outcomes included admission to the pediatric intensive care unit (PICU), admission to high-dependency unit, ventilator support, and oxygen therapy. The hazard ratios (HRs) were estimated using conditional Cox proportional hazards models with inverse probability of treatment weighting. Results: A total of 42 560 infants (mean age, 3.7 [SD, 1.4] days; 51.7% male) were included in the study (21 280 per group) with a median follow-up of 84 days (IQR, 70-99 days). Of the 481 hospitalizations for RSV-associated lower respiratory tract infection, 212 (44.1%) occurred in the nirsevimab group vs 269 (55.9%) in the RSVpreF vaccine group (between-group difference, −11.8% [95% CI, −18.1% to −5.5%]). Compared with the RSVpreF vaccine, passive infant immunization with nirsevimab was associated with a lower risk of hospitalization for RSV-associated lower respiratory tract infection (adjusted HR, 0.74 [95% CI, 0.61 to 0.88]). Compared with the RSVpreF vaccine, passive infant immunization with nirsevimab was associated with a lower risk of severe outcomes, including PICU admission (adjusted HR, 0.58 [95% CI, 0.42 to 0.80]), requiring ventilator support (adjusted HR, 0.57 [95% CI, 0.40 to 0.81]), or requiring oxygen therapy (adjusted HR, 0.56 [95% CI, 0.38 to 0.81]). The results were consistent across subgroups and in the sensitivity analyses. Conclusions and Relevance: Compared with maternal vaccination with the RSVpreF vaccine, passive infant immunization with nirsevimab was associated with lower risks of RSV-related hospitalization and severe outcomes. These findings reflect the first RSV season with use of these immunization strategies in mainland France; their use should be reevaluated in future studies.