Predicted vs observed effectiveness of outer membrane vesicle (OMV) vaccines against meningococcal serogroup B disease: Systematic review

Importance: Human serum bactericidal antibody levels (hSBA) are commonly used as an immune correlate of protection after vaccination against meningococcal disease. We performed a systematic review of how well this marker correlates with protection induced by outer membrane vesicle (OMV) vaccines against meningococcal B (MenB) disease. Objective: To compare vaccine effectiveness (VE) of OMV vaccines against MenB predicted by hSBA (predicted protection) to VE from clinical studies (observed protection). Data sources: Studies identified by searching Medline, Embase, Global Health, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and Database of Abstracts of Reviews of Effects. Study selection: Studies reporting hSBA after vaccination with OMV vaccines and subsequent efficacy/effectiveness in a MenB outbreak were included. Data extraction and synthesis: Data extraction and risk of bias assessments were performed by two independent investigators. Main outcomes and measures: Predicted VE and observed VE measured during MenB outbreaks. Results: We included 19 studies (eleven randomized controlled trials, six cohort studies, two case-control studies). Four different OMV vaccines were applied during nine different outbreaks (six countries, 1987-2009). A comparison between predicted and observed VE was possible using results from studies performed during five outbreaks. Predicted VE differed from observed VE by 2-59%, with greater differences observed in younger age groups. In general, predicted VE tended to be lower than observed VE. Conclusion and relevance: hSBA induced by OMV vaccines correlates moderately well with protection against MenB in older children and adults. The correlation was poor at very young ages, for which low VE was observed. (C) 2017 The British Infection Association. Published by Elsevier Ltd. All rights reserved.