Clonal vaccinia virus grown in cell culture fully protects monkeys from lethal monkeypox challenge.

The potential use of smallpox as an agent of bioterrorism has renewed interest in the development of a modern vaccine capable of replacing the standard Dryvax vaccine. Vaccinia virus (ACAM2000), clonally isolated from Dryvax and manufactured in cell culture, was tested for immunogenicity and protective activity in a non-human primate model. Cynomolgus monkeys vaccinated with ACAM2000, Dryvax, or ACAM2000 diluent (control) were challenged 2 months post-vaccination with a lethal, intravenous dose of monkeypox virus.