Estimate of AIDS Cases In U.S. Rises

By David Brown
Washington Post Staff Writer
Saturday, December 1, 2007

New government estimates of the number of Americans who become infected with the AIDS virus each year are 50 percent higher than previous calculations suggested, sources said yesterday.

For more than a decade, epidemiologists at the Centers for Disease Control and Prevention have pegged the number of new HIV infections each year at 40,000. They now believe it is between 55,000 and 60,000.

The higher estimate is the product of a new method of testing blood samples that can identify those who were infected within the previous five months. With a way to distinguish recent infections from long-standing ones, epidemiologists can then estimate how many new infections are appearing nationwide each month or year.

The higher estimate is based on data from 19 states and large cities that have been extrapolated to the nation as a whole.

The CDC has not announced the new estimate, but two people in direct contact with the scientists preparing it confirmed it yesterday.

What is uncertain is whether the American HIV epidemic is growing or is simply larger than anyone thought. It will take two more years of using the more accurate method of estimation to spot a trend and answer that question.

"The likelihood is that this bigger number represents a clearer picture of what has been there for the past few years. But we won't know for sure for a while," said Walt Senterfitt, an epidemiologist who is the chairman of the Community HIV/AIDS Mobilization Project (CHAMP), a New York-based activist organization.

There is evidence, however, that at least some of the higher number may reflect an uptick in infections in recent years. Information from 33 states with the most precise form of reporting showed a 13 percent increase in HIV infections in homosexual men from 2001 to 2005.

Ironically, the news comes less than two weeks after UNAIDS, the United Nations agency responsible for charting the course of the global epidemic, drastically reduced its estimate of the number of people living with the disease worldwide from 40 million to 33 million. The reason was the same: Crude methods of counting were replaced by better ones.

"People in the United States are under the impression that this is more of an international than a domestic issue," said Rowena Johnston, vice president for research at amfAR, an AIDS research foundation. "Yet these new CDC numbers are telling us that not only does this continue to be a serious problem, it is actually a larger one than we suspected."

A study describing the new U.S. estimate is under review at a scientific journal, Thomas W. Skinner, a CDC spokesman, said last night.

"We have to wait until this paper comes out, until it has gone through peer review, before we know what the new estimates look like," he said.

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