subject: AIDS Size of the problem [print this page] AIDS Size of the problem AIDS Size of the problem
WorldwideThe WHO and UNAIDS estimate that by the end of 1999,32.4 million adults and 1.2 million children worldwide willbe living with HIV, and that cumulatively since the startof the epidemic, 16.3 million people will have died from HIV/AIDS. The largest burden of infectionhas fallen on the developing world, particularly sub-Saharan Africa, which has close to 70% of the global totalfor HIV-infected people but is home to just 10% of the world. In adults aged between 15 and 49 yearsit is estimated that the prevalence of those living withHIV/AIDS in 1999 was 8% in sub-Saharan Africa, comparedto 0.56% in North America and 0.25% in western Europe. Recent studies have shown that although inthe developing world HIV is transmitted predominantlyby heterosexual intercourse, the female-to-male ratio ofinfected persons in sub-Saharan Africa is 1.2:1. There areseveral factors that might account for this, including thegreater efficiency of male-to-female HIV transmission through sex, and the younger age at first sexual contact forwomen.Elsewhere in the world, estimated new infections continueto increase markedly in south and southeast Asia,including India, although preventative programmes inThailand are beginning to be effective. Eastern Europeand central Asia, constituting Russia and the other formerstates of the USSR, also saw a marked increase in the estimatedreported number of HIV-infected people, rising byone-third, and largely driven by transmission throughinjecting drug use.United Kingdom and United StatesBy December 1999, 724636 cases of AIDS in adults hadbeen reported in the United States, and in the UnitedKingdom the total was 16457. These figures are thought tobe reasonably accurate and complete. Both countries haveseen a significant decrease in the number of new cases ofAIDS reported, a result of clinically effective antiretroviraltherapy; however, new infections with HIV continue tooccur and the prevalent population of people living withAIDS/HIV is rising. In North America and the UK the firstwave of the epidemic occurred in homosexual men.Although new infections among men who have sex withmen still arise, this group now accounts for less than 50%of those newly diagnosed with HIV infection per year inboth countries. In the USA an increasing proportion areamong injecting drug users who share needles or equipment,and in the UK among heterosexuals (Fig. 11.4). Thelatter is driven largely by an imported epidemic from sub-Saharan Africa, with only small numbers having acquiredthe infection through heterosexual contact within the UK.In the USA, 16% of AIDS cases have occurred in women,although the commonest route of transmission among suchwomen is injecting drug use (42%). The next most commonis heterosexual contact (40%).
