First use of Trumenba (MenB-fHbp) vaccine to control a nursery outbreak of serogroup B invasive meningococcal disease involving children previously immunised with Bexsero (4CMenB), England, November 2023

In November 2023, the UK Health Security Agency was notified of PCR-confirmed group B (MenB) invasive meningococcal disease (IMD) in a 3-year-old child (Case A), followed by probable IMD in a 2-year-old (Case B, culture and PCR tests negative) attending the same nursery. An incident management team (IMT) was convened. Both children were fully vaccinated with the MenB vaccine 4CMenB (Bexsero, GSK Biologicals). All 39 children attending the nursery and nine staff received ciprofloxacin chemoprophylaxis preceded by pharyngeal swabbing. Pharyngeal swabbing yielded two MenB isolates matching Case A. Antibiotic sensitivity testing and assessment of 4CMenB vaccine coverage using the meningococcal antigen typing system (MATS) revealed the strain was not covered by the 4CMenB vaccine. Although the alternative MenB vaccine, MenB-fHbp (Trumenba, Pfizer), is only licensed from 10 years and has never been given to children previously immunised with 4CMenB, the IMT considered the benefits of outbreak control outweighed potential risks. Two doses were given 4 weeks apart to 38 children (one family declined) and all staff; there were no serious adverse events. Our findings highlight the utility of swabbing to identify outbreak strains and provide first evidence for safe use of the MenB-fHbp vaccine in children previously vaccinated with 4CMenB.