Serological Studies on Two Epidemics of Varicella in a Babies Home

There were two epidemics of varicella in a babies home during about one year. All the infants suffered from the disease. The youngest infant with varicella was a 2-month-old male. The incubation period was estimated to be 15-18 days. CF antibody titers against varicella-zoster virus reached a peak by 4 weeks, and began to decline about 4 months after onset of the disease. The development and duration of IgG fluorescent antibody against varicella-zoster virus were similar to those of CF antibody titers. Some infants showed antibody response again during the second epidemic, and they were all subclinical. These antibodies belonged to IgG fraction of the sera. The antibody response in IgA and IgM fractions of the sera was not detected. Inapparent reinfections would play an important role in life-time immunity against varicella-zoster virus.