Monumental AIDS Breakthrough -- Or Is It?

Do we really understand the significance of the latest AIDS study's reported results? As we all know, statistics can be used in very creative ways that sometimes misleads the reader as to the effectiveness of a new drug or procedure.
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Today, there are over 5,000 new stories listed on Google News from media sources around the world announcing a groundbreaking breakthrough in the prevention of AIDS in Africa. Here is a sample of some of the headlines.

As these headlines suggest, and the underlying stories report, a vaginal gel applied by women prior to sexual encounters has been found in a double blind field test conducted in South Africa to reduce AIDS infection rates by 39%. Upon first hearing this, it would be natural to conclude that use of this gel would reduce reported cases of AIDS in Africa by 39%; or, if you were a woman living in Africa you might conclude that use of this gel might dramatically help you from getting infected in the future. You would not be alone in thinking this was a groundbreaking discovery as the announcement of these test results brought a standing ovation from the audience of scientists and NGO'ers at the International AIDS Conference in Vienna yesterday.

But, do we really understand the significance of this test's actual reported results? As we all know, statistics can be used in very creative ways that sometimes misleads the reader as to the effectiveness of a new drug or procedure.

It turns out that the test did result in 39% fewer infections, per year. The annual incidence rate for the treated group was 5.6 % more infections per year, while the control group that was administered a placebo experienced an annual rate of new infections of 9.1%. 5.6% is indeed 39% lower than 9.1%, in percentage terms, but sometimes measuring things in percentage terms can be deceiving.

In fact, when one looks behind the percentages at the actual numbers of people tested in the study the story is much less convincing. This was a very small test with only 843 women completing the study and they were evenly split between a treated group and a placebo, or control group that received no treatment. The actual number of new infections then were 38 women in the treated group and 60 women in the control group in a little over a year. You can see that there was a difference of only 22 women infected between the two groups, a very small number, especially relative to the 22 million of Africans who are infected with HIV/AIDS. If as few as ten less women in the control group had not contracted the disease, the study would have reported a minor 24 % decline in incidence and the entire story would have lost its newsworthiness.

Second, even with these reported lower rates of incidence of 39%, this improvement is an annual figure. The study does not say that over your lifetime you will be 39% less likely to get AIDS with this treatment, only that at the end of one year, you will have a 39% better chance of having not contracted it.

If you look over a woman's entire sexually active lifetime of, say twenty years, say age 15 to age 35 in Africa, even the treated women in this study in this highly infected AIDS environment would end up with over 70% of their members becoming infected. The good news is that the treated women do better than the untreated, the bad news is that 5.6% of them are still getting infected every year and this compounds to infection rates of over 70% of the entire population over a sexually active lifetime. Yes, the non-treated will see infection rates of over 85% over their lifetimes, but is this really as big a difference as the news headlines and news stories suggest. It is sort of like saying that smoking cigarettes is 39% safer per year than smoking crack, but what difference does that make if both end up killing you in the end.

Finally, for those of you who have not understood what moral hazard is when discussed in the financial crisis literature, here is a beautiful example. South Africa has announced they do not want to wait for more and bigger studies or for FDA approval, they want to immediately pursue distributing the gel to their female population as soon as possible. But, have they thought this through? What if as a result of the women in South Africa using this gel before intercourse, their boyfriends or husbands decide it is not necessary to use a condom. Condoms have been found to be very strong preventative measures against AIDS transmission, so if condom usage declined by just 30% it would completely wipe out any reported benefit associated with this new gel.

UNAIDS and the WHO are anxious to report some success in their fight against AIDS given that their attempts at finding a vaccine so far have failed and their donors are getting impatient. To date, they are betting on this gel for women and circumcision for men as tools to prevent AIDS transmission. But, their circumcision studies suffer the same problem with statistics that this gel study has, a 50% reported reduction in annual transmission rates with circumcision does not mean you will be 50% less likely to get the illness over your lifetime, just 50% less likely to be ill at the end of the first year. Because people have many sexual encounters over many years, such reductions in annual infection rates will do little to reduce the incidence of AIDS in Africa over a lifetime. In addition, the circumcision field studies are suspect because for obvious reasons it was impossible to conduct double blind experiments when circumcision is the treatment being examined, men have a way of knowing if their genitals have been cut and so may change behavior accordingly.

I came to the conclusion that much of the AIDS in Africa was due to the numerous and informal sexual affairs common in Southern African nations, found both among married and unmarried men, especially with a much smaller highly infected group of very sexually active women who trade sexual favors for material goods and money. I write about this explanation in an academic article published here.

Because the infection rates in many Southern African nations have reached epidemic proportions with more than 20% to 25% of all adults becoming infected, I also concluded that these highly infected nations should institute universal, compulsory, but confidential testing of all of their citizens over the age of 12. While you might argue that patient rights are violated by such compulsory testing, this minor social cost is more than outweighed by the social benefit of stopping an indiscriminate killer in the community. Once people know their status, they can act accordingly, or anti-viral drugs can be taken to dramatically lower the transmission rates and hopefully, over time, completely eradicate this scourge of death on the continent of Africa. Action needs to be taken to eradicate this killer, not just treat its victims or attempt to control its spread.

John R. Talbott is the bestselling author of eight books on economics and politics that have accurately detailed and predicted the causes and devastating effects of the current financial crisis. In 2007, Talbott authored two articles on achieving AIDS prevention and the need for confidential and compulsory universal testing in the most infected countries after having spent three months living in AIDS ravaged Botswana.

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