Prevention strategies: experience of varicella vaccination programmes.

Widespread immunization programmes have had a dramatic effect on the morbidity associated with varicella in the USA; mortality has declined by 66% (from 0.41 to 0.14 deaths / million population) and the reduction in hospitalizations is at least 4-fold (from 2.7 to 0.6/100,000 population) compared with the pre-vaccination era. Although varicella outbreaks have occurred in vaccination areas, these data may underestimate the true efficacy of the varicella vaccine, and there is still the potential for two-dose programmes, which have not yet been fully explored in the USA or Canada. Catch-up vaccination programmes have also been regarded as an important approach in susceptible individuals, including women of childbearing potential. Periodic exposure (boosts) to vaccines may potentially help prevent the reactivation of herpes zoster and accumulation of susceptibility in these at-risk groups. Pregnant women may also benefit from prophylaxis with varicella zoster immunoglobulin (VZIG) or possibly with aciclovir. Ongoing surveillance for the reactivation of herpes zoster and safety programmes are also highlighted as key recommendations.