A pound of prevention

A pound of prevention

There are no more excuses not to step up HIV prevention efforts, especially in the black and gay male population, after a new study has found that the incidence of new HIV cases in the U.S. may be much higher than previously thought. The study was conducted by the Centers For Disease Control and Prevention (CDC) and published in the August 6 issue of the Journal of the American Medical Association (JAMA).

“Incidence” is a measure of the risk of developing a certain condition within a specific time frame. In contrast, the term “prevalence” means the total number of cases of the disease in a population. In other words, while incidence measures the risk of getting a disease, prevalence measures how widespread it is.

The problem about incidence numbers is that they cannot be measured directly, but have to be estimated. So we never know whether an incidence rate is really true or way off.

Why then does it matter so much? Well, the success or failure of preventative measures are related to how much funding they get, and those numbers in return typically depend on what the incidence rates are. If a disease is estimated to have a low risk in a population, it’s not worth spending a lot of money to prevent it. On the other hand, if the risk is high, it will make sense to channel more money into preventative efforts, because in the end that process would save the country more money—and in the case of HIV prevention, ultimately more lives.

Earlier this month, a cover article in The New York Times reported that the U.S. for years had significantly underreported the incidence of new HIV infections occurring nationally each year. This article announced the new CDC study a few days before it was released in JAMA.

The study, based on an improved technique to diagnose HIV infection and estimate incidence rates, found that 56,300 people became newly infected with HIV in 2006, compared with the 40,000 figure the agency has cited as the recent annual incidence of the disease. Forty-five percent of infections were among black individuals and 53 percent among men who have sex with men. Why did it take the CDC so long to announce the new incidence rate for HIV, which is actually 40 percent higher than previously thought?

Frankly, the study had been anticipated for months, and the CDC had come under fire for not releasing the new data in a timely manner. Already back in June, an editorial in the British journal The Lancet had concluded: ”Either way, the figure shows that U.S. efforts to prevent HIV have failed dismally. The CDC must not fail U.S. citizens further by delaying the release of the data behind this fact.”

According to The New York Times article, the CDC has known of the new figures since last October, when the authors completed a manuscript and sent it to the first of three journals. But the agency refused to release the findings until they were published in a peer-reviewed medical journal. It can take quite a while for a scientific paper to pass through a journal’s review process, and apparently in this case a lot of complicated statistics were involved.

So now that the news is finally out, what should the core of prevention efforts be? It’s the same old story: Condoms, as the JAMA article notes, are highly effective in preventing the sexual transmission of HIV infection, but frequently are not used. We simply need to find better ways to reach out to the population at risk—especially blacks and gay males—with condom education and distribution.