Provisional country estimates of prevalent adult human immunodeficiency virus infections as of end 1994: a description of the methods

Abstract

Background: A country-by-country review of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) data was undertaken by the World Health Organization. This paper describes the methods used to make estimates of HIV prevalence.

Results: It is estimated that, globally, approximately 16.9 million adults were living with HIV infections at the end of 1994. The majority (66%) of the infections were in sub-Saharan Africa (over 11000000), followed by South and South East Asia (over 3000000). Estimated prevalence rates for HIV infection ranged from less than 1 per 100000 sexually active adult population to 18 per 100 (18%), with a median prevalence of 14 per 10000. In 50 countries the estimated HIV prevalence rate was less than 5 per 10000 sexually active adults. In 15 countries (all in sub-Saharan Africa) the prevalence rate was above 5%. The lowest estimated prevalence rates were seen in Central and East Asia and the highest in Central and Southern Africa.

Conclusions: Estimates of prevalent HIV infections are intended to give an indication of the magnitude of the HIV pandemic but, due to the difficulties in accurately assessing the levels of HIV infections in national populations, should be considered provisional.

PIP: During 1995, the World Health Organization (WHO) reviewed country-level data on adult HIV/AIDS cases and, in consultation with local and regional experts, revised its estimates of HIV prevalence as of the end of 1994. Data sources included cases reported to WHO by Member States, routine HIV surveillance, published studies, and blood banks. Globally, an estimated 16.9 million adults were infected with HIV at the end of 1994. About 66% of HIV infections were in sub-Saharan Africa and 18% in South and South East Asia. HIV prevalence ranged from less than 1/100,000 sexually active adults to 18/100, with a median of 14/10,000. 43% of adult HIV infections were in the least developed countries and another 50% in developing and middle-income countries. Although these statistics should be considered provisional, they provide an indication of the magnitude of HIV infection, provide a baseline for future monitoring, and may facilitate rational decision making regarding resource allocation. This paper includes a country-by-country listing of the estimated 1994 adult HIV prevalence rate per 100 population and the number of adult HIV infections, working estimates of adult HIV prevalence by subcontinent, and a case study (India) illustrating WHO's estimation technique.