[Evaluation of systematic anti-meningococcal vaccination strategy in French military recruits].

: The objective of the study was to assess the efficacy of meningococcal meningitidis vaccination among French military recruits, two years after the introduction of systematic vaccination. Protective efficacy (PE) was calculated using two epidemiological methods. The first was based on the incidence and density rates among vaccinated and unvaccinated subjects during the period when both groups were simultaneously available: PE = 100% (95% CI: 0-100%). The second was to compare the incidence density rates among vaccinated subjects with expected rates. The expected rates were calculated using a model involving adjustment of incidence rates observed before the introduction of vaccination. This second, more powerful method confirmed the efficacy of systematic vaccination for meningococcal meningitidis: PE = 100% (95% CI 30%-100%).