The effect of subcapsular meningococcal B + C vaccine on the prognosis of patients with meningococcal disease.

The effectiveness of the meningococcal Cuban vaccine (VaMengoc B + C) was examined in terms of the prognosis of patients who develop disease. All cases in the vaccinee age category admitted to the Meningococcal Disease Reference Centre, Rio de Janeiro between August 1990 and December 1993 were enrolled. Vaccine effectiveness (VE) was estimated from the relationship 1-OR, where the OR (odds ratio) was the exponential of the logistic regression coefficient for the association between death from meningococcal disease and previous vaccination. The case fatality rate for vaccinees was 6.1% and that for non-vaccinees was 10.6% (relative risk 0.58; 95% confidence interval [CI] 0.33-1.01). An overall protective effect of the vaccine against a fatal outcome was identified (VE 53%; 95% CI 12-75%) controlling for sex, age at time of immunization, elapsed time since vaccination and time between onset of disease and hospital admission. This study suggests that, for some people, even if the vaccine does not protect against the development of disease it may have a beneficial effect in terms of preventing a fatal outcome. This protective effect needs to be further investigated in a prospective cohort study specifically designed to evaluate the new generation of meningococcal vaccines.