The study was conducted in
Botswana to evaluate if pretreatment with Anti-HIV medications tenofovir
disoproxil fumarate and emtricitabine reduced the transmission of HIV in a
heterosexual population. Botswana has the second highest prevalence of HIV in
the world. Thus, any additional preventive measure could play an important role
in controlling HIV infection in this country.
The 1219 participants
included in the study were sexually active adults between 18 to 39 years of age
who tested negative for HIV and hepatitis B infection. Most of the participants
had only one sexual partner in the previous month. They were provided either
tenofovir disoproxil fumarate and emtricitabine, or a placebo for comparison of
effect. The participants were not aware whether they received an active
medication or placebo. They were also provided HIV preventive services like
counseling and free condoms and were followed up monthly.
The study found that the combination of tenofovir disoproxil fumarate
and emtricitabine decreased HIV infection by 62.2% when it was administered as
part of a comprehensive package of HIV-prevention services
. Ten participants were
infected with HIV among those taking the medication and 26 among those on
placebo. The patients who developed HIV despite the medication had lower drug
levels compared to those who did not develop the infection. This suggests that
they possibly were not strictly compliant with their medication intake.
Side effects like nausea,
vomiting and dizziness were more common in the group that took medication. Bone
mineral density appeared to be significantly decreased in some individuals on
Drug resistance was noted in
a participant who had unrecognized HIV infection and was administered the
medication. Hence, it is necessary to screen people carefully before they are
administered preventive Anti-HIV medication.
People taking medication to
prevent HIV could possibly become more promiscuous. Though this was not
observed in the current study, this fact should be borne in mind when a person
is put on preventive medications for HIV.
The study thus concluded that a combination of the Anti-HIV
medications, tenofovir disoproxil fumarate and emtricitabine, prevented HIV
infection among heterosexual men and women
. Further studies are necessary to establish
the use of these medications for preventing HIV infection.
Antiretroviral Preexposure Prophylaxis for Heterosexual HIV Transmission
in Botswana; Michael Thigpen et al; July 11, 2012 (10.1056/NEJMoa1110711)