The Botswana Harvard AIDS Institute partnership revealed the results of the Netefatso study, which was conducted between 2006 and 2008 among 325 HIV discordant couples in Botswana.
The study was meant to determine whether the use of the drug acyclovir, a drug widely used to treat Herpes Simple Virus-2 (HSV-2) could reduce the risk of HIV transmission when taken by people infected with both HIV and HSV-2.
Multiple studies have previously indicated that frequent genital herpes recurrences increase the amount of HIV in the blood and genital tract; it also showed that the HI virus is also shed from the genital herpes ulcers and persons with such ulcers transmit HIV more efficiently.
The researchers had hoped that acyclovir’s ability to suppress the herpes virus could also reduce the likelihood of HIV being transmitted from a person with HIV and HSV-2 during sexual intercourse.
The leader of the study and Botswana Project Director for the Botswana Harvard Partnership, Dr. Joseph Makhema, however, pointed out, “We did advice the couples to practice safe sexual intercourse.”
The Partners in Prevention HSV/HIV Transmission study was further conducted among 7 other countries in eastern and Southern Africa other than Botswana. Fourteen sites were established in the 7 countries, Tanzania, South Africa, Uganda, Kenya, Rwanda and Zambia and 3408 HIV discordant couples, where one had HIV and the other was HIV negative were used.
It was funded by the Bill and Melinda Gates foundation.
Dr. Makhema asserted that random sampling was blindly used during the study, where one group was given placebo and the other arm received acyclovir. There were apparently 41 infections in the acyclovir arm and 43 in the placebo arm. The transmissions occurred within the couple and not acquired from an outside partner.
Acyclovir suppressive treatment reduced the frequency of genital ulcers by 73% and the average amount of HIV in the blood by 40% compared to the placebo arm.
Makhema further explained, “A clinical trial of genital Herpes suppression in HIV discordant couples is the most direct way to see if we can make a person less likely to transmit HIV to their partner. The study did find that acyclovir significantly reduced genital ulcers due to HSV-2 and modestly reduced HIV levels in the blood, consistent with that the preliminary studies of HSV-2 suppressive treatment had shown. However, it appears that these effects were not sufficient to reduce the risk of HIV transmission.”
The study also determined whether acyclovir could slow HIV disease progression among individuals with HIV and HSV-2 who have CD4 T-cell counts that are too high for antiretroviral treatment according to current national guidelines. The number of participants in the acyclovir and placebo arms whose CD4 counts declined to below 200 and started treatment or died.
The study showed that HIV disease progression was slowed down by 17% by acyclovir. “Although the primary outcome of reducing HIV transmission was not observed, the study yielded important information that will inform HIV prevention research in a number of ways,” said Makhema.
He further said that the study proved worthwhile as it demonstrated that interventions must achieve a bigger reduction in HIV levels in order to reduce HIV transmission, especially among persons with high HIV levels.
Meanwhile, a study to establish whether ARV’s can reduce the sexual transmission of HIV discordant couples will be undertaken by BHP. The Thibelo study will recruit 120 HIV discordant couples.
The study aims to enroll 1750 couples from nine countries including Brazil, Malawi, India, South Africa, Zimbabwe, Thailand, Kenya and the USA.
HIV infected individuals with CD4 cell counts of 350-550 who have not taken Anti Retroviral Treatment (ART) will be enrolled with their HIV negative partners. Mothers who also enrolled for Prevention of Mother To Child Transmission (PMTCT) and meet the enrollment criteria will be considered for enrollment.
The study coordinator, Priti Dusara, said that the couples will be expected to be in the study for “the entire 60 months”.