Beginning in 1991, New Zealand experienced an epidemic of meningococcal disease; by the end of 2003 more than 5293 cases and 216 deaths had been reported. A “tailor-made” vaccine against the predominant strain was developed by Chiron Vaccines and a nationwide immunization program began in 2004. The staggered vaccine rollout program allowed an epidemiological analysis of its efficacy. Disease rates in vaccinated and unvaccinated areas were compared, adjusting for potential confounding variables such as disease progression over time, socio-economic status, seasonality and geographic region. This analysis showed the vaccine to be effective (Kelly et al. 2007; Kelly et al. 2008)
