Methisazone in Progressive Vaccinia

N-METHYLISATIN-β-THIOSEMICARBAZONE (methisazone) is an antiviral chemical of unquestioned activity both in vitro and in man. In cell-culture systems its activity is manifest by the failure of vaccinia-infected cells to synthesize a "late" structural protein of the virus. Thus, the drug prevents assembly of complete infectious virus particles if it is present during a major part of the replicative cycle.1 In man methisazone is a highly effective prophylactic drug upon exposure to smallpox.2 Ample statistical proof supports the practical usefulness of the drug in preventing serious disease, provided it is administered within one to three days after exposure. The therapeutic potential . . .