Now the risk of acquiring HIV by people who are HIV negative can be reduced by as much as 73% by taking a daily dose of tenofovir or tenovofir/emtricitabine. These antiretroviral tablets can be taken as a preventive medicine (PrEP – pre-exposure prophylaxis), and can prevent transmission of the virus from men to women and vice versa. These remarkable results from two studies conducted in Kenya, Uganda and Botswana were revealed recently.

In the first study, 4758 sero-discordant couples (in which one person had HIV infection and the other did not) in Kenya and Uganda were followed and the uninfected partners were randomized to one of the three study arms. They either received a once-daily tenofovir tablet or a tenofovir/emtricitabine tablet or a placebo pill. All couples were also provided with counselling and condoms at no extra charge. The results of this study showed that 62% fewer HIV infections occurred in the tenofovir arm compared to the placebo arm. Patients in the tenofovir /emtricitabine arm showed even better results with 73% fewer HIV infections compared to the placebo arm. This study, also known as the Partners PrEP trial, was conducted by the University of Washington’s International Clinical Research Center.

The second study conducted in Botswana enrolled 1200 men and women. They were randomized to receive either a once-daily tenofovir/emtricitabine tablet or a placebo pill. The results of this study revealed that 63% fewer HIV infections occurred in the tenofovir /emtricitabine arm compared to the placebo arm. This study, also known as the TDF2 trial, was conducted by the United States Centers for Disease Control.

Michel Sidibé, who serves as the Executive Director of the Joint United Nations Programme on HIV/AIDS (UNAIDS) said:

“This is a major scientific breakthrough which re-confirms the essential role that antiretroviral medicine has to play in the AIDS response. These studies could help us to reach the tipping point in the HIV epidemic.”

Generic forms of these antiretroviral drugs are available at very cheap costs in a number of countries with prices as low as 25 cents per tablet.

In a study conducted last year, commonly referred to us the iPrEx trial, HIV transmission was shown to drop by 44% among homosexual men who took a daily tablet of tenofovir/emtricitabine. This study had enrolled participants in six countries.

Dr Margaret Chan, WHO’s Director-General stated:

“Effective new HIV prevention tools are urgently needed, and these studies could have enormous impact in preventing heterosexual transmission. WHO will be working with countries to use the new findings to protect more men and women from HIV infection.”

To explore the potential role of prophylactic agents in preventing HIV, UNAIDS and WHO have been closely working with nations in sub-Saharan Africa, Latin America and Asia. The results of the current two studies will further enable us to defeat the deadly disease and will also inspire many people to get tested for HIV, discuss methods to prevent the transmission of the virus, and to approach services dedicated for prevention and treatment of HIV.

It is believed that only about 50% of the estimated 33 million people who have HIV know that they carry the virus. A significant impact will occur on AIDS response rate should more people across the globe test for the disease. The impact will be even more significant if people get access to systems that promise HIV prevention.

At this time no single method can offer complete protection against HIV, and as recommended by UNAIDS and WHO, people must make evidence-informed decisions on which combination of HIV prevention options suits them best. Should anti-retroviral drugs be considered for prevention, they must be combined with other methods suggested for prevention of HIV, such as the use of condoms, limiting the number of sexual partners, waiting longer before having sex for the first time, avoiding penetrative sex, and medical male circumcision.

Written by Anne Hudsmith