Annual HIV infection rates in the U.S. are 40 percent higher than previously believed, and continue to hit gay men, African-American, and Latino communities particularly hard, according to a study published by the Centers for Disease Control and Prevention (CDC) on Saturday. The study will be published in the August 6 edition of the Journal of the American Medical Association; publishers had planned to publish the study at the opening of the International AIDS Conference in Mexico City this week, but moved it up to Saturday.
The paper based on the CDC's research will indicate that the agency has been underreporting HIV infection rates by roughly 15,000 cases per year in the U.S. since the early 1990s. Whereas the annual average was previously believed to be about 40,000 cases per year, the CDC now thinks that rates were never that low, even at the low-point of infections in the early 1990s. The CDC now estimates the rate of infection to be between 55,000 and 58,000 new HIV cases per year, and to have been at those levels since the late 1990s. The article calculates incidence for a particular year—2006. For that year, the CDC now estimates 56,300 cases of HIV infection.
The new numbers are the combined result of statistical analysis and extrapolations with the results of a form of laboratory testing unavailable in previous years. Previous estimates were based only on the date of diagnosis—a highly unreliable method for a virus that can take a decade to manifest itself. The new test, by contrast, is able to distinguish between recent and long-term HIV infections, and so gives a more accurate picture of the rate of new infections as opposed to older cases. The new test can also give more exact information about infection rates in particular populations. The rate of infection was seven times higher among African-Americans and three times higher among Latinos than among whites. That means that African-Americans, who represent 13 percent of the U.S. population, formed 45 percent of the new infections in 2006. The research also confirms that gay and bisexual men represent the largest proportion of new infections, with 53 percent of new cases appearing in these populations.
The long-term underestimation of infection rates has proven shocking, and embarrassing, to the medical and political communities alike. In part, a historical trend analysis forming part of the article revising the CDC's estimates indicates that rates of HIV infection have remained roughly constant since the late 1990s—that is to say, through a decade of intensive education and prevention programs designed to reduce that number. With the newly adjusted infection rates, the appearance of progress in prevention over recent years has largely vanished. While the CDC still estimates an initial sharp plunge in HIV infections in the early 1990s—from a high of about 130,000 new cases per year in the mid-1980s to a low around 50,000 in the early 1990s—the organization finds little evidence of progress since then, and in fact see a moderate spike in numbers in the later 1990s that leveled off but never receded.
Dr. Julie L. Gerberding, Director of the CDC, said that, "If there is any good news here, it is hard to report it, but there is a little bit in the sense that while incidence rates are certainly too high, they are stable. That is important because a stable number of new infections in a world that has got more and more people with HIV and people with AIDS living in it suggests that we are keeping up with that pressure for transmission."
Still, it is difficult to avoid the logic of Dr. Kevin A. Fenton, who heads the CDC's prevention programs: "CDC's new incidence estimates reveal that the HIV epidemic is and has been worse than previously known."
Until now, the number of people in the U.S. living with HIV was estimated at around 1.1 million. That number will now require a depressing revision.