I'm Gwen Outen with the VOA Special English Health Report.

India is carrying out its first testing in humans of a vaccine to prevent infection with the virus that causes AIDS.

Thirty people will be injected with an experimental vaccine at the National AIDS Research Institute in the western city of Pune. This first part of the clinical trial will take about fifteen months. The purpose is mainly to test safety.

India has at least five million people with H.I.V. That is the second largest number after South Africa.

Human immunodeficiency virus, or H.I.V., suppresses the immune system. People become open to deadly infections as they develop AIDS. The United Nations says AIDS caused more than three million deaths last year.

There are different forms of H.I.V., and different groupings within each subtype. The vaccine being tested is designed to fight subtype C. That is responsible for the most AIDS infections worldwide. Scientists say the biggest problem in developing a vaccine is that the virus continually changes.

Researchers at Targeted Genetics in Seattle, Washington, and Columbus Children's Research Institute in Ohio developed the vaccine. The International AIDS Vaccine Initiative is involved as well. Testing is also being done in Germany and Belgium.

An estimated forty million people are living with H.I.V. Experts say there are fourteen thousand new infections each day. The virus is carried in blood and other body fluids.

People often do not know they have become infected. This is why, in the United States, some health experts recently suggested that almost all Americans get tested, not just those at high risk. They say this would lead to early treatment for more people and save money.

H.I.V. takes an average of about ten years to develop into AIDS. Antiretroviral drugs usually can slow the progress. But health officials in New York City recently reported about a man believed to have been infected last October. By December he had AIDS. The virus resisted most treatments.

Officials say the man had unprotected sex with other men. He also used crystal methamphetamine. Experts say this illegal drug may weaken the immune system.

Some experts say the man's immunity or drug use could explain the aggressive spread of his infection. They say it is too early to know if this case involves a new kind of H.I.V.

This VOA Special English Health Report was written by Cynthia Kirk. I'm Gwen Outen.