Immunity to chickenpox among school adolescents in Lebanon and options for vaccination.

Varicella infections cause substantial morbidity and mortality in adolescents and adults. The primary infection, chickenpox, results in lifelong immunity to chickenpox. A seroprevalence study carried on adolescents 15-18 years of age attending schools in Lebanon showed 96.6% immunity to varicella. The positive predictive value for immunity to chickenpox based on history alone was 97.4%, whereas the negative predictive value was 4.5%. Coming from a bigger family was a statistically significant predictor of immunity to chickenpox. In a developing country like Lebanon the merits and limitations of implementing universal varicella vaccination is discussed in relation to seroprevalence and socioeconomic factors.