Global Alert and Response (GAR)

WHO Report on Global Surveillance of Epidemic-prone Infectious Diseases - Human Immunodeficiency Virus and Acquired Immune Deficiency Syndrome (HIV/AIDS)


  • WHO and UNAIDS have estimated that by the end of 1999, 34.3 million people were living with HIV worldwide. It is also estimated that during 1999, 5.4 million people (including 620 000 children below 15 years of old) became infected. (Table 9.2).
  • Of the 5.4 million people newly infected with HIV in 1999, 4 million live in sub-Saharan Africa, the hardest-hit region. There are now more women than men among the 24.5 million adults and 1 million children estimated to be living with HIV/AIDS in sub-Saharan Africa.
  • Asia continues to have relatively low prevalence rates. There are an estimated 5.6 million adults and children living with HIV/AIDS in South-East Asia.
  • An estimated 1.3 million adults and children live with HIV in Latin America and the Caribbean. These are mainly men who have unprotected sex with other men and injecting drug users who share needles.
  • In 1999, Eastern Europe and Central Asia have seen the sharpest increase in HIV infections. Most of the 420 000 people living with HIV/AIDS in these countries have been infected through injecting drug use.
  • In the industrialized countries of North America, Western Europe and the Pacific, the availability of antiretroviral therapy has continued to reduce progression to AIDS, deaths and mother-to-child transmission of HIV. In most of these countries, however, the number of new HIV infections has remained relatively constant in recent years, with an estimated 1.5 million people living with HIV at the end of 1999.
  • Unsafe blood transfusions, a largely preventable mode of transmission, are causing a relatively small but still significant number of AIDS cases in many regions, particularly in the Middle East. Perinatal transmission, now also preventable to a large extent, is an important cause of AIDS in sub-Saharan Africa. However, paediatric AIDS is more likely to be underreported due to the diagnostic difficulties in resource-poor settings.
  • Assumed modes of HIV transmission in AIDS cases reported during recent years vary considerably from region to region For example, about 90% of reported AIDS cases in sub-Saharan Africa have reportedly been infected through heterosexual transmission. The proportion is much lower in other regions, although a substantial number of AIDS cases have been infected heterosexually in Asia, Latin America and North Africa/Middle East. The pattern in industrialized countries is mixed but it should be noted that heterosexual transmission is increasingly a cause of HIV infection in reported AIDS cases in these countries. In industrialized countries, Eastern Europe and Asia, a high proportion of reported infections is due to injecting drug use.