Release Notes: August 2006
This release of the IDB contains revised estimates and projections for 31 countries. For general information about how these estimates and projections are made, see Appendix B of the report Global Population Profile: 2002.
1. Expansion of the estimates and projections to age 100+ for all newly updated countries:
In order to better project countries with increasing numbers of people in the oldest ages, we are in the process of converting our projections to be done by single years of age up to 100 years and over. This change as well as the inclusion of new data was done for the following 14 countries:
- Sri Lanka
- Western Sahara
2. Revised projections for 16 countries with HIV/AIDS using new methodology and procedures:
In addition to expanding age distributions to age 100+, and incorporating new data on the standard components of demographic change (mortality, fertility, migration), these 16 countries have undergone additional analyses to update the estimated effects of HIV/AIDS. The U.S. Census Bureau compiles HIV prevalence information for developing countries in its HIV/AIDS Surveillance Data Base. This database contains over 93,000 records from various publications and surveillance reports. HIV prevalence points taken from this database are the basis for projecting HIV prevalence, estimating AIDS mortality, and estimating and projecting the impact of AIDS on the number of orphaned children.
To obtain estimates of AIDS-related mortality, a new application developed at the Census Bureau incorporates estimates of HIV prevalence from the Estimation and Projection Package (EPP) - an epidemiologically realistic model developed and used by the World Health Organization (WHO) and the Joint United Nations Programme on HIV/AIDS (UNAIDS). EPP produces a national "best fit" curve of adult HIV prevalence using sentinel surveillance data pertaining to pregnant women. We use country-specific adult HIV prevalence estimates from EPP for years from the beginning of the epidemic to 2010.
The Census Bureau application applies assumptions from the WHO/UNAIDS Epidemiological Reference Group about the age/sex distribution of HIV incidence, sex ratio of new infections, mother-to-child transmission rate, and disease progression. The model allows for competing risk of death and projects HIV incidence implied by the EPP estimates of HIV prevalence through 2010, assuming a decline in HIV incidence of 50 percent by 2050. The model now includes the impact of antiretroviral therapy on survival of AIDS patients.
This methodology works in conjunction with the Census Bureau's cohort component Rural-Urban Projection program (RUP), which is used to prepare population estimates and projections. RUP is used to produce "With AIDS" and "Without AIDS" scenarios.
The first series, "With AIDS," shows what has happened in each country because of AIDS mortality and its demographic consequences. Second, a hypothetical "Without AIDS" series shows what the Census Bureau's modeling work indicates would have happened if a country had not been affected by the HIV/AIDS epidemic. This modeling takes into account not only lower death rates but also associated changes to a country's age-sex structure and, indirectly, the combined effects of lower mortality and changing population composition on demographic indicators. The "Without AIDS" series currently assumes the same fertility rates (based on observed data) as the "With AIDS" series, and thus underestimates what fertility might have been in the absence of AIDS. In the "With AIDS" series the number of births decrease as a result of mortality-induced reductions in the numbers of women of reproductive age.
Currently, only the "With AIDS" series is shown in the IDB.
The 16 countries are:
- Dominican Republic
3. The following area was updated to include new data and/or analysis, but the age distribution was not expanded to 100+:
- Puerto Rico