Sixteen years of global experience with the first refrigerator-stable varicella vaccine (Varilrix).

Without vaccination, chickenpox (varicella) will affect almost every person in the world during their lifetime. The burden of disease due to varicella is often unrecognized. Varilrix is a varicella vaccine derived from the Oka strain of varicella virus. The vaccine, as a frozen formulation, was licensed for use in 1984 and was the first commercially available varicella vaccine. It subsequently became the first refrigerator-stable varicella vaccine; its development commenced in 1991 and it has been licensed for use since 1994. Varilrix is indicated for use in high-risk groups, potentially immunocompromised individuals, and healthy subjects in many countries. This article reviews data from extensive worldwide experience with the refrigerator-stable version of the vaccine, including information derived from its use in over 10,000 individuals participating in clinical trials investigating its immunogenicity, efficacy, effectiveness, and safety, as well as postmarketing data including its use in universal mass vaccination programs. Sixteen years of clinical and postmarketing experience with the same formulation represents the longest and most extensive experience with a refrigerator-stable varicella vaccine worldwide. Varilrix, in conjunction with the trivalent measles-mumps-rubella vaccine Priorix, has also been the basis for clinical development of the tetravalent measles-mumps-rubella-varicella vaccine (Priorix-Tetra).