Time from infection to AIDS computed.

Time from infection to AIDS computed

Based on data from patients who acquired AIDS from blood transfusions, British scientists reported last week that children under the age of 5 at the time of infection develop their first symptoms of AIDS about two years after transfusion--more than four times earlier than the average eight-year "incubation time' seen in patients between the ages of 5 and 59. The statistical analysis, based on figures from 297 U.S. cases, also found that patients 60 years and older develop AIDS at an average of 5.5 years after transfusion.

Researchers at the University of London analyzed data provided by the Centers for Disease Control (CDC) in Atlanta to determine the average time from infection to development of AIDS. The scientists point out in the Aug. 20 NATURE that, although these incubation times may not prove to be identical to those seen among other groups of AIDS patients, knowing the exact date of infection from transfusion makes such studies a unique and valuable resource in understanding AIDS.

David R. Cox of the London group told SCIENCE NEWS that the data from the under-5 age group are the most conclusive, and incubation times for older patients may have to be updated as more data become available. CDC epidemiologist Harold Jaffe, who did not take part in the current study, said in an interview that "it looks like the rate of disease progression in AIDS from transfusions is more or less the same as in [AIDS from other sources].' Knowledge of average incubation times, however, does not mean someone at high risk can relax after a certain number of years following probable exposure to the AIDS virus, says Jaffe. "I think we [scientists] all believe that there is no such thing as a maximum incubation period [after which you are safe],' he says.