Epidemiologic effects of varicella vaccination

A key question in immunization with live varicella (Oka) vaccine is whether the positive effects of individuals being vaccinated at a young age could be counterbalanced by an overall increase in morbidity due to a potential increase in the number of individuals who contract varicella at an older age. A theoretical transmission model is used to examine the overall population effects of routine varicella immunization of US preschool children and the implementation of a catch-up program. Most plausible assumptions about the Live varicella (Oka) vaccine and levels of coverage produced an overall decrease in morbidity in the simulation studies. Vaccine efficacy studies should be designed to obtain estimates of the characteristics of vaccination that are required for looking at long-term, overall effects of vaccination programs.