Three Things You Don't Know About Aids In Africa
So what do we learn from this? First, the fact that Africa is so heavily
affected by HIV has very little to do with differences in sexual behavior and
very much to do with differences in circumstances. Second, and perhaps more
important, there is potential for significant reductions in HIV transmission in
Africa through the treatment of other sexually transmitted diseases.
Such an approach would cost around $3.50 per year per life saved. Treating
AIDS itself costs around $300 per year. There are reasons to provide AIDS
treatment in Africa, but cost-effectiveness is not one of them.
It won't disappear until poverty does.
In the United States, the discovery of the HIV epidemic led to dramatic
changes in sexual behavior. In Africa, it didn't. Yet in both places,
encouraging safe sexual behavior has long been standard practice. Why haven't
the lessons caught on in Africa?
The key is to think about why we expect people to change their behavior in
response to HIV-namely because, in a world with HIV, sex carries a larger risk
of death than it does in a world without HIV. But how much people care about
dying from AIDS ten years from now depends on how many years they expect to
live today and how enjoyable they expect those future years to be.
My studies show that while there have been very limited changes in sexual
behavior in Africa on average, Africans who are richer or who live in areas
with higher life expectancies have changed their behavior more. And men in
Africa have responded in al¬most exactly the same way to their relative
"life forecasts" as gay men in the United States did in the 1980s. To
put it bluntly, if in¬come and life expectancy in Africa were the same as they
are in the United States, we would see the same change in sexual behavior-and
the AIDS epidemic would begin to slow.
There is less of it than we thought, but it's spreading as fast as ever.
According to the UN, the HIV rates in Botswana and Zimbabwe are around 30
percent, and it's more than 10 percent in many other countries. These estimates
are relied on by policymakers, re¬searchers, and the popular press. Yet many
people who study the AIDS epidemic believe that the numbers are inflated.
The reason is quite simple: bias in who is tested. The UN's estimates are
not based on diagnoses of whole populations or even a random sample. They are
based on tests of pregnant women at prenatal clinics. And in Africa, sexually
active women of child¬bearing age have the highest rates of HIV infection.
To eliminate the bias, I took a new approach to estimating the HIV infection
rate: I inferred it from mortality data. The idea is simple: In a world without
HIV, we have some expectation of what the death rate will be. In a world with
HIV, we observe the actual death rate to be higher. The difference between the
two gives an estimate of the number of people who have died from AIDS, and we
can use that figure to estimate the prevalence of HIV in the population.
My work suggests that the HIV rates reported by the UN are about three times
too high. Which sounds like good news-but isn't. The overall number of
HIV-positive people may be lower than we thought, but my study, which estimated
changes in the infection rate over time, also drew a second, chilling
conclusion: In Africa, HIV is spreading as quickly as ever.