MORE THAN 3 MILLION CONTRACTED HIV WORLDWIDE IN '96, HEALTH OFFICIALS SAY.

Byline: Lawrence K. Altman The New York Times

More than 3 million people, mostly under age 25, have become newly infected with the AIDS virus this year, officials of the United Nations and the World Health Organization said Wednesday. They stressed the need for more vigorous programs to prevent further spread of the virus because it is being transmitted in all countries.

The new cases bring to nearly 23 million the total number who are infected. In the 15 years since the discovery of AIDS, an additional 6.4 million people - 5 million adults and 1.4 million children - have died. Of those deaths, 1.5 million will have occurred in 1996.

Of the 8,500 new infections each day, 7,500 are in adults and 1,000 in children. About 42 percent of all those living with HIV, the virus that causes AIDS, are women, and the proportion is growing.

The figures are estimates because most Third World countries vastly underreport official AIDS figures for reasons largely related to crude disease surveillance systems, the Geneva-based agencies said in reporting them a few days before World AIDS Day on Sunday.

New outbreaks of HIV infection are erupting in Eastern Europe, the former Soviet Union, India, Vietnam, Cambodia, China and elsewhere, said Dr. Peter Piot, who heads the United Nations' global AIDS program. Surveys show surging rates of infection among sex workers, truck drivers and migrant workers who are transmitting the disease in wider areas in many of the countries.

In Vietnam, for example, infection rates have climbed to 38 percent in 1994 and 1995, from 9 percent in 1992. In Cambodia, 10 percent of people who offered to donate blood in Phnom Penh in 1995 were infected, compared with 0.1 percent in 1991.

The HIV epidemic is ``strengthening its grip on the world's most vulnerable populations,'' Piot said. The surges provide ``clear warning that HIV infections are not abating, and unless these countries put their muscle behind prevention programs now, the epidemic will reach tragic proportions,'' he said.

As long as HIV exists somewhere, it threatens people everywhere, and ``that is why the richer industrial countries must take responsibility to fight the epidemic on all fronts,'' Piot said.

Africa is the continent hardest hit by AIDS, and civil strife in Rwanda and Zaire threatens to aggravate the toll. New surveys in Zimbabwe and Botswana have found that up to 40 percent of pregnant women are infected, Piot said in an interview.

But in Zaire, surveys have found a 2 percent to 4 percent rate among pregnant women. Piot said his agency was supporting research to determine why the rates are increasing in some areas and declining in others.

``As more women die of AIDS, the number of orphans will rise exponentially,'' Piot said. The United Nations is sponsoring research to develop effective but less costly means of preventing transmission from mother to infant. AIDS has led to a loss of productivity among young people, a drop in life expectancy of up to 10 years, and declining gross national products in many countries in Africa, Piot said.

Elsewhere, transmission rates are soaring in some countries that had been relatively unaffected but had done little to prevent further spread. AIDS prevention requires political support, ``but politicians do not get elected by preventing a problem that'' they cannot prove they prevented, Piot said.

``The epidemic is starting to skyrocket in Russia and the Ukraine, where transmission is from everything - injecting drugs, poor hygiene, and heterosexual and homosexual intercourse,'' Piot continued.