Varivax (Merck & Co).

Varivax is a live-attenuated varicella vaccine developed and launched in the US by Merck & Co for the treatment of chickenpox [413319]. The vaccine uses the Oka strain of the varicella virus licensed from the Biken Institute at Osaka University in Japan [178223]. By June 2001, Merck was also developing the vaccine for use in adults for herpes zoster infection [413319]. The FDA required post-marketing studies as a condition for its approval of Varivax, which was granted in March 1995 [174416]. The Centers for Disease Control & Prevention Advisory Committee on Immunization Practices recommended that Varivax should be administered at the same time as the measles, mumps and rubella vaccine. Unvaccinated children between the ages of 19 months and 13 years should be vaccinated by the time they are 13 years old [180148]. Varivax, from its launch in the spring of 1995 to the end of the third quarter 1995, produced sales of US $60 million [196542]. In June 2000, a second generation of Varivax, Varivax II, was launched for vaccination against chickenpox in individuals 12 months of age and older. Varivax II prevents the transmission of chickenpox with exactly the same safety and efficacy profile as Varivax; however, the new Varivax II has the advantage of being refrigerator-stable [371871].