# Post-marketing safety profile of meningococcal group B vaccines: a real-world disproportionality analysis of the VAERS database, 2015Q1–2025Q3

## TL;DR

This study examines the safety of MenB vaccines using real-world data from 2015 to 2025, finding mostly expected side effects but some rare, unlabeled events.

## Contribution

The study provides updated real-world safety data for MenB vaccines using VAERS and identifies rare adverse events not previously labeled.

## Key findings

- Most reported events were expected, such as fever and injection site reactions.
- Some unlabeled events like pallor and hypotonia showed elevated reporting odds ratios.
- Serious events occurred earlier after vaccination compared to non-serious events.

## Abstract

Serogroup B meningococcal (MenB) disease remains a serious public health concern. Recombinant protein-based vaccines have been licensed since the mid-2010s, but ongoing surveillance is needed to capture rare or long-term adverse events.

We analyzed reports submitted to the Vaccine Adverse Event Reporting System (VAERS) from 2015Q1 to 2025Q3,with data available through 30 September 2025. Cases explicitly identifying MenB vaccines were included. Events were coded with MedDRA, and disproportionality analyses were conducted using Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), and Empirical Bayes Geometric Mean (EBGM). Subgroup analyses assessed differences by age, sex, seriousness, and coadministration.

A total of 16,611 reports were identified, of which 19.9% were serious. Most events reflected expected reactogenicity such as fever, syncope, headache, and injection site reactions. Several unlabeled events, including pallor and hypotonia, showed elevated RORs. Time-to-onset analyses demonstrated clustering within 2 days of vaccination across all strata, with serious events occurring earlier than non-serious events. No novel syndromic clusters were observed.

MenB vaccines show a favorable safety profile in real-world use. While most events align with established product information, a small number of disproportionate but unlabeled events merit continued pharmacovigilance.