Studies Examine Reducing Risk Of Vertical HIV Transmission While Breastfeeding
HIV-positive women who arebreastfeeding can reduce the risk of vertical HIV transmission if they take theantiretroviral drug nevirapine for up to six months after giving birth,according to five CDC- and NIH-funded studies conducted in Africaand India and presented Monday at the 15th Conference on Retroviruses and OpportunisticInfections inBoston, the New York Times reports.
In one of the five studies, HIV-positive women in Kenya took a combination ofantiretrovirals beginning in their 34th week of pregnancy until they had beenbreastfeeding for six months. Their infants received the standard single doseof nevirapine after birth to prevent vertical transmission. Of the 497 infantsin the Kenyan study, 12, or 2.4%, were HIV-positive one week after birth.Fifteen infants, or 3%, contracted the virus from breastfeeding eight days to12 months after birth, the study found.
In a similar study conducted in Malawi,more than 3,000 infants received one of three treatment regimens during thefirst 14 weeks following birth. The study found that after nine months, HIVincidence was lowest at 3.1% among infants who received nevirapine for 14weeks, compared with 10% in the control group, which received the standardsingle dose of nevirapine at birth followed by one week of treatment with anotherantiretroviral (Altman, New York Times,2/5).
In the other studies -- conducted by Brooks Jackson of Johns Hopkins University and colleagues in Ethiopia,India and Uganda between2001 and 2007-- 2,000 infants received either nevirapine or a placebo for sixweeks. After six months, the risk of HIV or death was one-third less among theinfants who received nevirapine than among the other infants, the study found (Reuters Health, 2/4).
According to the Times, the studies' findings "open theway" for new strategies to prevent vertical transmission in developingcountries, where HIV-positive women often must breastfeed because of a lack ofaccess to formula or clean water, strong cultural traditions of breastfeedingor fear of stigmatization for not breastfeeding. Anthony Fauci, director ofNIH's National Institute of Allergy andInfectious Diseases,said the studies "could serve as the basis of a new standard ofcare," adding that the next step is to "determine the optimal timefor treating mothers and infants" (New York Times, 2/5).
In related news, anotherstudy presented Monday at the conference found that treating genital herpeswith the drug acyclovir does not prevent or reduce the risk of HIVtransmission, the San Francisco Chronicle reports. According to the Chronicle,many researchers believed that treating herpes would reduce susceptibility toHIV because numerous studies in the past 20 years have found that herpesincreases the risk of HIV by creating lesions that serve as points of entryinto the body for the virus.
The study was conducted among 3,000 men who have sex with men in New York, Peru,San Francisco and Seattle,as well as women in Africa (Russell, SanFrancisco Chronicle, 2/4). Half of the participants took acyclovir andhalf took a placebo. The study found that people who tookacyclovir to treat herpes contracted HIV at the same rate as those who took aplacebo (Fox, Reuters Health, 2/4). The study also found thatacyclovir reduced herpes lesions by different percentages in different groups:32% among African women, 41% among MSM in Peruand 50% among MSM in the U.S.
According to the Chronicle, one possible reason the herpestreatment did not prevent HIV is that it does not eradicate herpes, meaningthat people who take acyclovir continue to have occasional genital ulcers,which increase the risk of HIV. A possible solution would be to increase thenumber of acyclovir pills beyond two daily, the Chronicle reports.According to Connie Celum, a researcher at the University of Washington who led the study, previous studieshave shown no significant improvement in herpes suppression with higher doses (SanFrancisco Chronicle, 2/5). In addition, Rowena Johnston, vice presidentof research for the American Foundation for AIDSResearch, said itis possible that herpes causes immune cells to circulate actively in the body,increasing the risk of HIV (Reuters Health, 2/4).
Celum said that despite the study's "disappointing" findings, shewill continue another study currently under way that aims to determine whetherherpes treatments block HIV among couples in which one partner is HIV-positive.That study is expected to end in June, and results are expected in about oneyear, the Chronicle reports (San Francisco Chronicle,2/5).
Reprintedwith permission from kaisernetwork.org. You can view the entire Kaiser Daily HIV/AIDS Report, search the archives, and sign upfor email delivery at kaisernetwork.org/email . The Kaiser Daily HIV/AIDS Reportis published for kaisernetwork.org, a free service of The Henry J. KaiserFamily Foundation.