Antiviral Drug Used for Fighting Infections in AIDS Patients May Work Against Smallpox

Cidofovir, an antiviral drug approved by the FDA in June 1996 to treat cytomegalovirus retinitis -- a "sight-threatening" infection commonly found in those with AIDS -- may be effective in treating smallpox, a disease that many fear could become a bioterrorist weapon, USA Today reports. Researchers at the U.S. Army Medical Research Institute of Infectious Diseases in March 1998 found that the drug, produced by Gilead Sciences under the brand name Vistide, could prevent a pox disease in primates that is similar to smallpox in humans. Both diseases cause respiratory problems, fever and rash. Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said it would be "unethical" to expose humans to smallpox, which was eradicated in 1977, in order to test the drug, but a government study on the effectiveness of diluting the existing stock of smallpox vaccine may give researchers an opportunity to see how the drug reacts to the virus. Smallpox is highly infectious and kills about one-third of those infected. If study volunteers react to the vaccine, they will first be treated with immunoglobulin. However, if that does not work, cidofovir will be used as a "backup," Fauci said (Rubin, USA Today, 10/22).