Results from two studies reveal that a daily antiretroviral tablet taken by people who do not have HIV infection can reduce their risk of acquiring HIV by up to 73%. Both daily tenofovir and daily tenofovir/emtricitabine taken as preventive medicine (PrEP – pre-exposure prophylaxis) can prevent heterosexual transmission of HIV from men to women and from women to men.
The Partners PrEP trial, conducted by the University of Washington’s International Clinical Research Centre, followed 4758 sero-discordant couples (in which one person had HIV infection and the other did not) in Kenya and Uganda. Couples received counselling and free male and female condoms. The uninfected partner took a once-daily tenofovir tablet or a tenofovir/emtricitabine tablet or a placebo pill. There were 62% fewer HIV infections in the group receiving tenofovir and 73% fewer HIV infections in the group that took tenofovir/emtricitabine than in the group receiving the placebo.
The TDF2 trial, conducted by the United States Centres for Disease Control, followed 1200 men and women in Botswana who received either a once-daily tenofovir/emtricitabine tablet or a placebo pill. The antiretroviral tablet reduced the risk of acquiring HIV infection by roughly 63% overall in the study population of uninfected heterosexual men and women.
“This is a major scientific breakthrough which re-confirms the essential role that antiretroviral medicine has to play in the AIDS response,” said Michel Sidibé, Executive Director of the Joint United Nations Programme on HIV/AIDS (UNAIDS). “These studies could help us to reach the tipping point in the HIV epidemic.”
The medicines are available generically in many countries at prices as low as US$ 0.25 per tablet. In November 2010, the iPrEx trial among men who have sex with men in six countries reported a 44% reduction in HIV transmission among those who took a daily tenofovir/emtricitabine tablet.
“Effective new HIV prevention tools are urgently needed, and these studies could have enormous impact in preventing heterosexual transmission,” said Dr Margaret Chan, WHO’s Director-General. “WHO will be working with countries to use the new findings to protect more men and women from HIV infection.”
UNAIDS and WHO have already been working with countries in sub-Saharan Africa, Latin America and Asia to explore the potential role of pre-exposure prophylaxis in HIV prevention. This news will encourage more people to get tested for HIV, discuss HIV prevention options with their partners and access essential HIV services.
It is currently estimated that only about half of the 34 million people living with HIV know their HIV status. An increase in the uptake of testing for HIV would have a significant impact on the AIDS response, particularly if more people gain access to new HIV prevention technologies in light of the new findings.
UNAIDS and WHO recommend that individuals and couples make evidence-informed decisions on which combination of HIV prevention options is best for them. No single method is fully protective against HIV. Antiretroviral drugs for prevention need to be combined with other HIV prevention options. These include correct and consistent use of male and female condoms, waiting longer before having sex for the first time, having fewer partners, medical male circumcision and avoiding penetrative sex.
For more information on different types of sexually transmitted infections, prevention of STIs, treatments and effects on fertility, see Sexually Transmitted Infections (STIs).