Trends in Brazil's AIDS epidemic

Trends in Brazil's AIDS epidemic

At the beginning of the Brazilian AIDS epidemic, most of the people becoming infected with HIV were men who have sex with men. The majority lived in Brazil’s biggest cities, Rio de Janeiro and São Paulo. However, the epidemic soon affected more than just MSM, and since 1993 more cases of AIDS are attributed to heterosexual transmission than homosexual transmission.^{14 15 16} Among adult males (13 years and over), 17 percent of AIDS cases were due to heterosexual sex from 1980 to 1995, compared to 35 percent in 2000 and over 46 percent in 2007. (The exposure category among 15-20 percent of male AIDS cases each year is unknown.) Similarly, among adult women, heterosexual sex accounted for nearly 95 percent of all AIDS cases in 2007 compared with 75 percent before 1995.¹⁷

From before 1995 until 2007, the share of injecting drug use as the exposure category in new AIDS cases declined from 27.5 percent to around 10 percent among adult males, and 21.9 percent to just over 4 percent among adult females.¹⁸

At the start of the epidemic, HIV transmission through blood transfusion and blood products was also common. In 1986 HIV blood-screening tests were made compulsory at blood banks in São Paulo, and by 1988 this policy was implemented nationwide, signalling the start of a decline in HIV-transmissions occurring through these routes.¹⁹

Between 1996 and the turn of the century, the introduction of antiretroviral therapy led to a significant drop in the level of AIDS-related mortality.²⁰ The number of cases where HIV was transmitted from pregnant mothers to their children also declined in this period, due to the availability of ARVs, which significantly reduce the chances of transmission occurring through this route.²¹

The number of Brazilians living with HIV is around 730,000 an increase of approximately 70,000 since 2001.²² The overall AIDS incidence rate has also increased, possibly due to the delayed effect of HIV infections in previous years. The rise in AIDS incidence has not led to an increase in the AIDS mortality rate, which significantly declined since the introduction of treatment in 1996 from 9.6 annual deaths per 100,000 people, to 6.0 in 2006.^{23 24} It should be noted, however, that the North and North-East regions of Brazil have seen increases in AIDS mortality over the course of the decade, whereas there has been a marked decline in the southeast.^{25 26}

Although men still account for the majority of infections, women represent an increasing share of the epidemic with the ratio of male-to-female AIDS cases shrinking from 15-to-1 in 1986 to 1.5-to-1 in 2008.^{27 28} It has become increasingly clear that young people are bearing the brunt of the epidemic, and that poor people and those with a low level of education are at a higher risk of becoming infected. ²⁹ HIV transmission resulting from contaminated blood products and blood transfusions is now thought to be practically non-existent,³⁰ and studies in major cities have pointed to a decline in HIV prevalence among IDUs.^{31 32}