The AIDS Pandemic

Posted by • June 7th, 2013

The HIV–AIDS pandemic is now in its fourth decade. The latest article in our new Global Health series describes how HIV–AIDS has been transformed from a death sentence into a manageable illness and outlines the need for continued and coordinated international efforts.

It was not until the third decade of the epidemic that the world’s public health officials, community leaders, and politicians united to combat AIDS. In 2001, the United Nations General Assembly endorsed a historic Declaration of Commitment on HIV/AIDS and renewed this commitment in 2011. These actions resulted in the formation of the Global Fund to Fight AIDS, Tuberculosis, and Malaria to finance anti-AIDS activities in developing countries. In 2003, President George W. Bush announced the President’s Emergency Plan for AIDS Relief (PEPFAR), which allocated billions of dollars to countries hardest hit by AIDS.

Clinical Pearls

• How many people were estimated to be living with HIV in 2011?           

UNAIDS (United Nations Program on HIV/AIDS) estimates that in 2011, 34.2 million people were living with HIV, as compared to 29.1 million in 2001; 2.5 million had become newly infected, a 22% decline as compared to 2001, and 1.7 million died, a decline of 26% from 2005. Similarly, new infections among neonates and infants have decreased from a peak of 570,000 in 2003 to 330,000 in 2011 as a result of interventions to prevent mother-to-child transmission.

• What regions of the world are most affected by HIV, and in what regions has the spread of HIV begun to decline and where has it increased?         

According to the authors, sub-Saharan Africa continues to be the most affected continent, followed by Eastern Europe and the Caribbean. A special case is southern Africa, where HIV has become hyperendemic, with adult HIV prevalence rates as high as 31% in Swaziland, 25% in Botswana, and 17% in South Africa, reaching an astonishing 54% among women between the ages of 30 and 34 years in Swaziland. Even within a country, differences in HIV prevalence can vary widely by region and risk group. Thus, in 2010 within South Africa, provincial antenatal  HIV prevalence ranged from 18.4% in the Northern Cape to 39.5% in KwaZulu Natal. Men who have sex with men, female sex workers, users of injection drugs, truck drivers, fishermen, and military personnel are disproportionately affected around the world. There is also heterogeneity in epidemiologic trends. Whereas HIV spread is slowing in most regions, HIV incidence continues to increase in Eastern Europe and several Asian countries. There is also a resurgence of HIV infection due to increased risk behavior among men who have sex with men in several European cities, such as a 68% increase in sexual risk behavior among such men in Amsterdam — in spite of high rates of HIV testing and access to antiretroviral therapy (ART). At the same time,  HIV is spreading to previously unaffected populations, such as injection drug users in parts of Africa and men who have sex with men across Asia and Africa, where widespread homophobia drives these men underground.

Figure 1. World Map of Prevalence of HIV Infection.

Morning Report Questions

Q: What are current recommendations regarding the initiation of treatment of HIV/AIDS?

A: With the life expectancy of an HIV-infected person under treatment approaching that of an uninfected person, there has been an increased emphasis on starting ART therapy much earlier in the course of infection. The revised 2012 U.S. Department of Health and Human Services guidelines recommend ART for all HIV-infected individuals. These recommendations are based on evidence of ongoing HIV replication on disease progression. Additionally, because ART use prevents transmission of HIV in discordant couples, the guidelines recommend that ART be offered to all HIV-infected individuals to reduce the risk for their sexual partners. In contrast to the U.S. and European guidelines, the World Health Organization guidelines continue to recommend treating all persons with CD4 counts less than or equal to 350, recognizing the limitations of cost and availability in many countries. However, all guidelines strongly recommend ART for persons, regardless of CD4 count, who are pregnant or who have a history of an AIDS-defining illness, tuberculosis, or coinfection with HIV and hepatitis B, and, more recently, the guidelines were updated to recommend ART for HIV-discordant couples.

Table 1. Guidelines for the Initiation of Antiretroviral Drugs in Adults with HIV Infection.

Q: What are the principles of preexposure prophylaxis (PrEP)? 

A: Use of ARTs prior to sex is referred to as preexposure prophylaxis. Precoital use of 1% tenofovir gel reduced HIV acquisition by 39% in women and daily oral tenofovir and emtricitabine among men who have sex with men reduced HIV acquisition by 44%, with greater efficacy observed among individuals who achieved high levels of adherence in both trials. Daily tenofovir or tenofovir plus emtricitabine reduced HIV acquisition by 66% and 73%, respectively, among uninfected partners in HIV serodiscordant partnerships, and in young heterosexuals in Botswana. While these studies are encouraging, two studies produced conflicting results, finding no efficacy with either oral or gel Tenofovir. The explanation for these discrepant studies may be due to low adherence to the drug regimens or differences in mucosal penetration. Recently, the Food and Drug Administration approved daily oral Truvada (emtricitabine and tenofovir disoproxil fumarate) for PrEP in combination with safer sex practices to reduce the risk of sexually acquired HIV infection in adults at high risk.

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