Reactogenicity and immunogenicity of a live-attenuated refrigerator-stable varicella vaccine (OKA strain) in healthy seronegative subjects age 10 months to 12 years.

This study assessed the immunogenicity and reactogenicity of a live-attenuated varicella vaccine (Oka strain), Varilrix in Indonesian children age 10 months to 12 years. A total of 300 seronegative subjects were stratified into three age subgroups (10 months to < 3 years, 3 years to < 7 years and 7 to 12 years) and all received a single-dose of Oka strain varicella vaccine. One solicited local symptom (injection site soreness) was reported during the 43-day post-vaccination follow-up period. Fever (29/295; 10%) was more prevalent than rash (3/295; 1%) but the incidence of grade 3 fever (defined as axillary temperature of >39 degrees C) was infrequent. No grade 3 unsolicited events and no serious adverse events were reported. The vaccine proved to be immunogenic in all age groups; all but one subject seroconverted for anti-varicella antibodies 43-days post-vaccination. This study demonstrated that the live-attenuated varicella vaccine (Oka strain) was well tolerated and immunogenic with no safety issues when administered as a single dose primary vaccination to healthy, seronegative Indonesian subjects age 10 months to 12 years.