Science / Medicine : Study to Investigate Extent of HIV Cases

Allegheny County, Pa. is to become the focus of the first federal attempt to estimate how many Americans are infected with the human immunodeficiency virus--a long-unanswered question that could play a central role in future public-health planning and AIDS prevention.

The pilot study, to include 350 randomly chosen households, is to begin in January under the auspices of the U.S. Centers for Disease Control, officials said. Its purpose is to develop guidelines for a broader nationwide survey.

Participation will be voluntary and all information collected will be anonymous. Participants will be asked to give a blood sample and to complete a questionnaire including questions on drug use and sexual behavior.

Earlier attempts to study the prevalence of the virus have been thwarted by concerns about privacy and community selection. For example, federal plans for a survey in Washington, D.C. were suspended last summer amid concerns that the selection was racially motivated.