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

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 from 1984 to 1999 residing in New Zealand. Therefore, it was eligible for meningococcal B vaccination from 2004 to 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 a percentage. There were 1,143,897 eligible cohort members with 135 missing information on gender, 16,245 missing ethnicity, and 197,502 missing deprivation. Therefore, only 935,496 cohort members 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, the data suggests 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.