Effectiveness of a Group B outer Membrane Vesicle Meningococcal Vaccine in Preventing Hospitalization from Gonorrhea in New Zealand: a Retrospective Cohort Study

Abstract

Gonorrhea is a major global public health problem with emergence of multiple drug-resistant strains with no effective vaccine. This retrospective cohort study aimed to estimate the effectiveness of the New Zealand meningococcal B vaccine against gonorrhea associated hospitalization. The cohort consisted of individuals born 1984-1999 residing in New Zealand, therefore eligible for meningococcal B vaccination during 2004-2008. Administrative datasets of demographics, customs, hospitalization, education, income tax and immunization, were linked using the national Integrated Data Infrastructure. The primary outcome was hospitalization with a primary diagnosis of gonorrhea. Cox’s proportional hazards models were applied with a Firth correction for rare outcomes to generate estimates of hazard ratios. Vaccine effectiveness estimates were calculated as 1-Hazard Ratio expressed as percent. There were 1,143,897 eligible cohort members, with 135 missing information on gender, 16,245 missing ethnicity and/or 197,502 missing deprivation hence 935,496 were included in the analysis. After adjustment for gender, ethnicity and deprivation, vaccine effectiveness (MeNZB™) against hospitalization caused by gonorrhea was estimated to be 24% (95% CI 1-42%). In conclusion, vaccination with MeNZB™ significantly reduced the rate of hospitalization from gonorrhea. This supports prior research indicating possible cross protection of this vaccine against gonorrhea acquisition and disease in the outpatient setting.