2004 Report on the global AIDS epidemic
The estimates and data provided in the following tables relate to the end of 2003 and the end of 2001 unless stated otherwise. These estimates have been produced and compiled by UNAIDS/WHO. They have been shared with national AIDS programmes for review and comments, but are not necessarily the official estimates used by national governments. For countries where no recent data were available, country-specific estimates have not been listed in the table. In order to calculate regional totals, older data or regional models were used to produce minimum estimates for these countries.
The estimates are given in rounded numbers. However, unrounded numbers were used in the calculation of rates and regional totals, so there may be minor discrepancies between the regional/global totals and the sum of the country figures.
The general methodology and tools used to produce the country-specific estimates in the table have been described in a series of papers in Sexually Transmitted Infections 2004, 80 (Suppl 1). The estimates produced by UNAIDS/WHO are based on methods and on parameters that are informed by advice given by the UNAIDS Reference Group on HIV/AIDS Estimates, Modelling and Projections.
This group is made up of leading researchers in HIV and AIDS, epidemiology, demography and related areas. The Reference Group assesses the most recent published and unpublished work drawn from research studies in different countries. It also reviews advances in the understanding of HIV epidemics, and suggests methods to improve the quality and accuracy of the estimates.
Based on suggestions from the Reference Group, new software has been developed to model the course of HIV epidemics and their impact. These changes in procedures and assumptions have resulted in improved estimates of HIV and AIDS for 2003. To allow readers to assess recent trends in the epidemic, we also present end-2001 estimates developed using the same methodology and data as for the end-2003 estimates.
The new estimates in this report are presented together with ranges, called ‘plausibility bounds’. These bounds reflect the certainty associated with each of the estimates. The wider the bounds, the greater the uncertainty surrounding an estimate. The extent of uncertainty depends mainly on the type of epidemic, and the quality, coverage and consistency of a country’s surveillance system. A full description of the methods used to develop plausibility bounds can be found in Sexually Transmitted Infections 2004, 80 (Suppl 1).
Adults in this report are defined as men and women aged 15–49 years. This age range captures those in their most sexually active years. While the risk of HIV infection continues beyond 50 years, the vast majority of people who will become infected are likely to have done so by this age.
Since population structures differ greatly from one country to another, especially for children and older adults, the restriction of ‘adults’ to 15–49-year-olds has the advantage of making different populations more comparable. This age range was used as the denominator in calculating the adult HIV prevalence proportion. It is also consistent with previous estimates.
These estimates include all people with HIV infection, whether or not they have developed symptoms of AIDS, alive at the end of 2003 and the end of 2001. For countries marked with one asterisk (*) a population-based survey with HIV prevalence measurement will be conducted in the near future. For countries marked with two asterisks (**), new surveillance has been conducted recently but the results were not available for inclusion in the estimation process. For some countries where sufficient data from the last six years were not available, no estimates have been made.
Estimated number of adults and children living with HIV at the end of 2003 and 2001. Children are defined as those aged 0–14 years.
Estimated number of adults living with HIV at the end of 2003 and 2001.
To calculate the adult HIV prevalence proportion, the estimated number of adults living with HIV at the end of 2003 was divided by the 2003 adult population (aged 15–49) and similarly for 2001.
Estimated number of women (aged 15–49) living with HIV at the end of 2003 and 2001.
Estimated number of children under age 15 living with HIV at the end of 2003 and 2001.
Estimated number of adults and children who died of AIDS during 2003 and 2001. Estimates and ranges marked with three asterisks (***) have been informed by data from vital registration systems.
Estimated number of children aged 0-17 years as of end-2003 who have lost one or both parents to AIDS.
Depending on the reliability of the data available, there may be more or less uncertainty surrounding each estimate. While a measure of uncertainty applies to all estimates, in this report the plausibility bounds are presented for the following estimates:
These indicators are taken from the 2001 United Nations General Assembly Special Session on HIV/AIDS, and give a reasonable estimate of relatively recent trends over time in HIV infection in countries with generalized epidemics (prevalence over 1%) that are predominantly heterosexually driven. The number of pregnant women attending antenatal clinics (ANC) aged 15–24 years whose test results were positive is divided by the number of pregnant women aged 15–24 years who had an HIV test. The median of the capital city sites and year of the last report are included.
These indicators are recommended for reporting against the goals of the 2001 United Nations General Assembly Special Session on HIV/AIDS in countries with low-level epidemics (prevalence under 1%; prevalence in specific populations at higher risk below 5%) or concentrated HIV epidemics (prevalence under 1%; prevalence in specific populations at higher risk above 5%). Most of these data are from routine sentinel surveillance. For each of the populations the table gives the year of the most recent report and the median for the surveillance sites in the capital city. The specific populations at higher risk of HIV exposure in the tables include:
Before 2000, the definition of ‘high-risk-sex’ varied between surveys and thus the values presented should be considered as indicative of the risk level in the respective countries. Attempts have been made to present standardized results, but the values given should not be used to compare risk levels between countries.
The sources are denoted as follows: ‘a’ Behavioural Surveillance Surveys (FHI[U31]), ‘b’ Botswana AIDS Impact Survey ([U32]2001), ‘c’ Multi-Indicator Cluster Survey (UNICEF[U33]), ‘d’ Demographic and Health Survey, ‘e’ Survey of Youth and Adolescent Reproductive Health and Sexual Behaviours in Mozambique (INJAD, 2001[U34]); ‘f’ Reproductive Health Survey (CDC[U35]). For indicators derived from an additional survey, the year of the survey is denoted as follows: ‘v’ 1998, ’w’ 1999, ‘x’ 2000, ‘y’ 2001, ‘z’ 2002.
Percentage of 15–24-year-old respondents (female and male) who know that a healthy-looking person can be infected with the AIDS virus.
Percentage of 15–24-year-old respondents (female and male) who could identify two ways a person could avoid getting the AIDS virus (using a condom and avoiding multiple partners) and reject three misconceptions (know that a healthy-looking person can have the AIDS virus and two local misconceptions, such as that mosquito bites can transmit AIDS virus).
Percentage of 15–19-year-old respondents (female and male) who reported having sex before the age of 15.
Proportion of 15–24-year-old respondents who had sex with a non-marital, non-cohabiting partner in the last 12 months[U36], of all respondents reporting sexual activity in the last 12 months.
Percentage of 15–24-year-old respondents who say they used a condom the last time they had sex with a non-marital, non-cohabiting partner, of those who have had sex with such a partner in the last 12 months.
Year of the survey in which knowledge and behavioural data was collected.
