childhood immunization flesh-eating disease varilrix CHILDHOOD IMMUNIZATION Varivax III is currently available from Merck Frosst to help protect children, age 12 months andolder, against chickenpox In clinical trials, antibodies against the varicella virus were observed at 4 to 6 weeks following vaccination with VARIVAX ŽIII in 97% of children 12 months to 12 years of age.