AIDS: Researchers at the National Institute of Allergy and Infectious Diseases (NIAID) report that the activation of the immune system by other stimuli results in an increase in HIV replication. Sharilyn Stanley, M.D., NIAID Director Anthony S. Fauci, M.D., and colleagues inoculated 13 asymptomatic HIV-infected people and 10 uninfected people with tetanus booster shots to stimulate their immune systems. Blood samples were drawn at intervals for up to 42 days later. The amount of HIV in the blood increased 2-fold to 36-fold in all 13 HIV-infected people following immunization, and the virus was more readily grown from the blood cells of 9 of these patients. Researchers also found that of the 10 uninfected volunteers, 7 were more easily infected with HIV in the test tube after immunization than prior to it. The data suggests that ongoing activation of the immune system may play a role in HIV pathogenesis and enhance the susceptibility of uninfected people to HIV. NIAID is planning a follow-up study to determine whether HIV-infected people can benefit from antiretroviral therapy to block the transient viremia associated with immunizations.