Varicella-zoster virus (Oka strain) (VZV)

Varicella-zoster virus (VZV), specifically the Oka strain, is a human alphaherpesvirus responsible for causing varicella (chickenpox) and herpes zoster (shingles). The Oka strain is a live-attenuated version of the virus, originally isolated from a child with chickenpox and subsequently passaged in cell culture to reduce its virulence while maintaining its immunogenicity. It serves as the primary biological component in vaccines such as Varivax and Zostavax, which are designed to elicit protective humoral and cellular immune responses. In the context of pharmacology, VZV is the target of several antiviral medications, including acyclovir and its prodrug valacyclovir, which inhibit viral DNA polymerase to prevent replication. While the Oka strain is significantly less pathogenic than wild-type VZV, it can still establish latency in sensory ganglia and carries a small risk of reactivation or causing complications in severely immunocompromised individuals.

Other names

Human alphaherpesvirus 3 (Oka strain)vOkaOka/Merck strainLive attenuated varicella-zoster virusHHV-3 (Oka strain)

Antiviral agents inhibit viral DNA replication by targeting the DNA polymerase or helicase-primase complex, while vaccines induce active immunity through the presentation of attenuated viral antigens.