CDC underestimated new HIV cases in U.S.

ATLANTA (AP) | The number of Americans infected by the virus that causes AIDS each year is much higher than the government has been estimating, U.S. health officials reported, acknowledging that their numbers have understated the level of the epidemic.

The country had roughly 56,300 new HIV infections in 2006 - a dramatic increase from the 40,000 annual estimate used for the past dozen years. The new figure is the result of a better blood test and new statistical methods and not a worsening of the epidemic, officials said.

But it likely will refocus U.S. attention from the effect of AIDS overseas to what the disease is doing to this country, said public health researchers and officials.

“This is the biggest news for public health and HIV/AIDS that we’ve had in awhile,” said Julie Scofield, executive director of the National Alliance of State and Territorial AIDS Directors.

The revised estimate by the Centers for Disease Control and Prevention and the methodology behind it were to be presented Sunday, the opening day of the international AIDS conference in Mexico City.

Since AIDS surfaced in 1981, health officials have struggled to estimate how many people are infected each year. It can take a decade or more for an infection to cause symptoms and illness. One expert likened the new estimate to adding a good speedometer to a car. Scientists had a good general idea of where the epidemic was going; this provides a better understanding of how fast it’s moving now.

“This puts a key part of the dashboard in place,” said David Holtgrave, chairman of the Department of Health, Behavior and Society at Johns Hopkins University’s School of Public Health.

Judging by the new calculations, officials think annual HIV infections have been hovering at about 55,000 for several years.

“This is the most reliable estimate we’ve had since the beginning of the epidemic,” said Dr. Julie Gerberding, the CDC’s director, adding that other countries may adopt the agency’s methodology.

According to current estimates, about 1.1 million Americans are living with the human immunodeficiency virus. Officials plan to update that number with the new calculations, but don’t think it will change dramatically, a CDC spokeswoman said.

The new infection estimate is based on a blood test that for the first time can tell how recently an HIV infection occurred. Past tests could detect only the presence of HIV, so determining which year an infection took place was guesswork. The old 40,000 estimate was based on that guesswork.

The new estimate relies on blood tests from 22 states where health officials have been using a new HIV-testing method that can distinguish infections that occurred within the past five months from those that were older. The improved science will allow more real-time monitoring of HIV infections. Now, CDC officials say, the estimate will likely be updated every year.

Yearly estimates allow better recognition of trends in the U.S. epidemic. For example, the new report found that infections are falling among heterosexuals and injection-drug users.

But the CDC also found that infections continue to increase in men who have sex with men, who accounted for more than half of HIV infections in 2006. Also, more than a third of those with HIV are younger than 30.