The Demographic Impact of HIV/AIDS

As part of its research work programme, the United Nations Population Division studies the demographic impact of AIDS in the world. In its 1998 Revision of world population estimates and projections, special attention is given to those developing countries which are hardest-hit (population of 1 million or more and an adult HIV prevalence of 2 per cent or more) or, because of their large population size, exhibit a large share of the developing world's HIV infections.

Among those countries, 29 are in Sub-Sahara Africa (Benin, Botswana, Burundi, Burkina Faso, Cameroon, Central Republic of Africa, Chad, Congo, Côte d'Ivoire, Democratic Republic of Congo, Eritrea, Ethiopia, Gabon, Guinea Bissau, Kenya, Lesotho, Liberia, Malawi, Mozambique, Namibia, Nigeria, Rwanda, Sierra Leone, South Africa, Togo, Uganda, United Republic of Tanzania, Zambia, Zimbabwe), 3 in Asia (Cambodia, India and Thailand), and 2 in Latin America and the Caribbean (Brazil and Haiti). Of the 30 million persons in the world currently infected by HIV (UNAIDS, 1997), 26 million (85 per cent) reside in these 34 countries. In addition, 91 per cent of all AIDS deaths in the world have occurred in these 34 countries.

The 1998 Revision shows a devastating toll from AIDS with respect to mortality and population loss. In the 29 hard-hit African countries that are studied, life expectancy at birth is currently estimated at 47 years, 7 years less than what could have been expected in the absence of AIDS (Figure 1). The demographic impact of AIDS is even more dramatic when one focuses only on the hardest hit countries. For example, the average life expectancy at birth in the 9 countries with an adult HIV prevalence of 10 per cent or more is projected to reach 48 years in 1995-2000 whereas it would have reached 58 years in the absence of AIDS, a loss of 10 years. This group includes Botswana, Kenya, Malawi, Mozambique, Namibia, Rwanda, South Africa, Zambia and Zimbabwe. Yet, the demographic impact of HIV/AIDS is expected to intensify in the future. By 2010-2015, the average life expectancy at birth in these countries could be only 47 years (Figure 2). In the absence of AIDS, it would have been expected to reach 63 years. This represents 16 years lost to AIDS. However, in none of the 34 countries, is the population expected to decline because of the AIDS epidemic.

Figure I. Life Expectancy at Birth in 29 African Countries With and Without AIDS Between 1985-1990 and 2010-2015 Source: United Nations Population Division, World Population Prospects: The 1998 Revision, forthcoming.

Figure II. Life Expectancy at Birth in the Seven Hardest Hit Countries Between 1985-1990 and 2010-2015 Source: United Nations Population Division, World Population Prospects: The 1998 Revision, forthcoming.

In Botswana, the hardest-hit country, one of every 4 adults is infected by HIV. Life expectancy at birth is expected to drop from 61 years in 1990-1995 to 47 years in 1995-2000. In the absence of HIV/AIDS, it would have been expected to reach 65 years in 1990-1995 and 67 years in 1995-2000. Due to the impact of AIDS, life expectancy is projected to further fall to 41 years by 2000-2005; this is 29 years less than expected in the absence of HIV/AIDS. Mainly due to the mortality impact, population growth in Botswana has been significantly reduced. The average annual population growth rate of 3.5 per cent per year in 1980-1985 has fallen to 2.9 per cent in 1990-1995 and will likely further fall to 1.9 per cent in 1995-2000 and 1.2 per cent in 2000-2005 (Figure 3). In the absence of AIDS, Botswana's population would have experienced growth above 2.5 throughout the 1990-2005 period. Because of the mortality impact of AIDS, Botswana's population by 2015 is expected to be 20 per cent smaller than it would have been in he absence of AIDS. Nevertheless, because of high fertility, Botswana's population is still expected to nearly double between 1995 and 2050.

Figure III. Annual Population Growth Rates With and Without AIDS Between 1985-1990 and 2010-2015 Botswana Source: United Nations Population Division, World Population Prospects: The 1998 Revision, forthcoming.

In Zimbabwe, the second hardest hit country, one of every five adults is infected. Life expectancy at birth was estimated at 52 years in 1990-1995 whereas it would have been 61 years in the absence of AIDS. It is projected to further decrease to 44 years in 1995-2000 and 41 years in 2000-2005. In the absence of AIDS, it would have been expected to rise to 66 years by 2000-2005. As in Botswana, the demographic impact on population growth in Zimbabwe has been staggering. Estimated at 3.3 per cent in 1980-1985, the annual growth rate fell to near 2 per cent in 1990-1995 and will likely further fall to 1.4 per cent in 1995-2000 and under 1 per cent in 2000-2005. In the absence of AIDS, Zimbabwe would have experienced growth of 2.4 per cent per year in 1995-2000 and probably still be at 2 per cent per year in 2000-2005 (Figure 4). Because of the heavy toll on human lives, Zimbabwe's population in 2015 is expected to be 19 per cent lower than it would have been in the absence of the AIDS epidemic.

Figure IV. Annual Population Growth Rates With and Without AIDS Between 1985-1990 and 2010-2015 Zimbabwe Source: United Nations Population Division, World Population Prospects: The 1998 Revision, forthcoming.

The South African epidemic began later than in Zimbabwe. One of every 8 adults was infected by the virus in 1997. Due to the later start, the demographic impact is yet to come. By 1990-1995, life expectancy at birth (estimated at 59 years) was barely affected by HIV/AIDS. However, projections show that by 2005-2010, 21 years of life expectancy at birth will be lost to AIDS: the level of life expectancy is expected to be just 45 years against 66 years in the absence of AIDS. Population growth, while remaining positive, is also expected to decrease faster because of the AIDS epidemic. South Africa’s annual growth rate is expected to decrease from 1.9 per cent in 1990-1995 to 0.3 per cent by 2005-2010; in the absence of HIV/AIDS, the population growth rate in 2005-2010 would have been around 1.5 per cent (Figure 5). By 2015, South Africa’s population is expected to be 16 per cent lower than it would have been in the absence of the AIDS epidemic.

Figure IV. Annual Population Growth Rates With and Without AIDS Between 1985-1990 and 2010-2015 South Africa Source: United Nations Population Division, World Population Prospects: The 1998 Revision, forthcoming.

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