(Population Today, August/September 2002) Long viewed as an African success story, Botswana is still booming economically, thanks to wise management of revenues from its diamond trade. But with the highest prevalence of HIV/AIDS in the world (39 percent of adults ages 15 to 49 have the disease), Botswana now is struggling to channel its wealth into developing a valuable nontradable commodity: its people’s health.

Ironically, the country’s economic achievement does not translate into easy answers in dealing with the epidemic. In fact, in some ways, prosperity makes for tougher choices. As appealing as it would be to fund a massive and immediate medication program, such an effort alone would yield only short-term gains and could encourage risky behavior.

Beginning this year, Botswana is undertaking a countrywide anti-HIV program. It consists of medication (with antiretroviral drugs, which extend the lives of those with the virus but do not provide a cure) and education intended to bring about behavior change — that is, condom use. Funding and drugs for the program come from sources including the Bill & Melinda Gates Foundation, the Merck Company Foundation, and the government of Botswana.

Before the program advances, policymakers must know more about its potential effects, cautions Warren C. Sanderson, professor of economics and history at the State University of New York at Stony Brook and senior research scholar at the International Institute for Applied Systems Analysis in Laxenburg, Austria. For instance, would it make a difference whether more money went to medication or to behavioral change? And what kind of difference? “It is not obvious,” he notes, “what the right mix of the two is. Poorly designed programs can … pile more suffering upon those who have already suffered gravely.”

To help determine the right mix, he modeled the effects of pursuing medication-only, behavior-change-only, and combination programs. He started by dividing the current population into those with and without HIV. He then divided the HIV group into three smaller groups: those showing no symptoms and taking no medication, those showing no symptoms but taking medication, and those with full-blown AIDS. These groups roughly correspond with the stages of the disease’s progression. He also disaggregated the population by age, gender, level of education, initiation to sexual activity, and riskiness of sexual behavior.

He simulated exposure of these populations to HIV, factoring in current and projected incidence and prevalence rates, length of time an infected person typically spends in the various disease stages, and life expectancy.

HIV prevalence data in Botswana are based solely on tests of women who have sought prenatal care. These data are biased and have to be adjusted before they can be used in a model. Sanderson noted that no nationwide data on the HIV prevalence among African men currently exist, a factor that complicated his research.


Sanderson’s research shows the limitations of medication and behavior-change programs in controlling the epidemic. As seen in the accompanying figures, an all-out medication campaign (Sanderson believes the maximum coverage of such a campaign would be 70 percent of those who need it, since there are always people who will not be reached) would keep more people alive in the short-term but would lose effectiveness in the long run. Even with this large a program, there would be 1.3 million AIDS deaths between 2003 and 2046. Further, after initially boosting female life expectancy at birth, by 2019 the medications-only program would not be able to raise life expectancy above its currently depressed level of 42 years.

AIDS Projections for Botswana, by Type of Intervention, 1993-2046

Source: Warren Sanderson, “The Demographic Impact of HIV Medication Programs” (presented at the annual meetings of the Population Association of America, Atlanta, May 9, 2002).

Reasons for this poor performance in the long-term include direct and indirect effects of the program itself. Although medication programs can lower the degree to which people on medication are infectious, thus lowering the rate at which the disease spreads through unprotected sexual contact, they increase the number of people who have HIV and can spread it to others; lead to drug resistance; and reduce the fear associated with developing the deadly disease, thereby increasing the population’s likelihood of engaging in risky sex.

An all-out behavior-change program (one that motivates nonmonogamous people to use condoms 70 percent of the time) would not produce any visible results until 2012, contributing to a lowering of the population in the short-term, but would eventually save more lives — roughly half a million — than medications alone. And a behavior-change-only program would raise female life expectancy at birth fairly dramatically — from the current 42 years to 58 by 2046 — but only after it falls to around 35 in the near term.

The alternative to any program is not to do anything new. In the long run, this would lead to fewer annual deaths by 2046 than would the all-out medications-only program, but total population would be 400,000 people fewer, and life expectancy would be only 36 years instead of 40.

Other findings, based on a wide range of possible scenarios, include:

  • Comparing an all-out medication program with one that combines a 20 percent medication rate and a 20 percent behavior-change goal. The combination of very modest programs can bring about nearly the same positive results as a much larger medication-only program but does no better in elevating female life expectancy at birth, which would be only about 40 years.
  • Combining programs of all types with a not-yet-developed vaccine, hypothetically administered in 2012. The basic results do not change. A large medication program yields only modest advantages over a smaller medication program; roughly the same results as a modest condom-use program; and roughly the same results as a very modest combination program.


Unlike many of its neighbors, Botswana can afford to sustain a large, expensive medication program begun with international aid. But large medication-only programs compete with behavior-change programs for resources, and they may hasten the development of medication-resistant strains of the virus. In the long run, implementing a modest medication program while emphasizing education that promotes behavior change is probably the best approach, although many people now living with AIDS won’t be around to see its merits.

Allison Tarmann is editor of Population Today. 

For More Information

The research this article describes was undertaken for the International Institute for Applied Systems Analysis in Laxenburg, Austria, with funding from the European Commission. For questions on the research, contact Warren Sanderson by e-mail: wsanderson@notes.cc.sunysb.edu.