MenB Vaccines May Not Be Effective During a Meningococcal Outbreak

The serogroup B meningococcal (MenB) vaccines MenB-FHbp and MenB-4C are not likely to provide herd protection and therefore may not effectively protect recipients from a meningococcal outbreak, according to a recent study.

Currently, little data exists about the impact of MenB-FHbp and MenB-4C on meningococcal carriage and herd protection.
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To explore this further, the researchers collected 4225 oropharyngeal swab specimens during 4 carriage surveys over 11 months from a convenience sample of 3802 students recommended for vaccination. Participants were also administered questionnaires.

Real-time polymerase chain reaction analysis, slide agglutination, and whole-genome sequencing were used to test isolates. University records and the state immunization registry were consulted to verify vaccination history.

Results of the study indicated that total prevalence of meningococcal (11% to 17%) and genotypically serogroup B carriage (1.2% to 2.4%) were stable during each round. The researchers noted that, while none of the participants had carried the outbreak strain, neither 1 to 3 doses of of MenB-FHbp nor 1 to 2 doses of MenB-4C was found to lower total or serogroup B carriage prevalence.

“While few participants completed the full MenB vaccination series, limiting analytic power, these data suggest that MenB-FHbp and MenB-4C do not have a large, rapid impact on meningococcal carriage and are unlikely to provide herd protection in the context of an outbreak response,” the researchers concluded.

—Christina Vogt

Reference:

McNamara LA, Dolan Thomas J, MacNeil J, et al; Oregan Meningococcal Carriage Team. Meningococcal carriage following a vaccination campaign with MenB-4C and MenB-FHbp in response to a university serogroup B meningococcal disease outbreak—Oregon, 2015-2016. J Infect Dis. 2017;216(9):1130-1140. https://doi.org/10.1093/infdis/jix446.