� A drug usually used in the development world to prevent contagion of HIV from mother to shaver persists in the breast milk and blood of the mothers, putting them and their babies at risk for developing drug-resistant strains of the virus, according to researchers at the Stanford University School of Medicine.
The researchers found that the dose, nevirapine, corset in the blood and breast milk of the infected mothers for at least two weeks. During that time, the computer virus has sizeable opportunity to transform itself into drug-resistant strains of HIV, the human immunodeficiency virus that causes AIDS, which tin be very difficult to treat.
"In the little term, nevirapine is better than zilch," said David Katzenstein, MD, professor of infectious diseases and principal investigator of the study. "But in the long term, I'm concerned around conferring resistance. If you're talking around resistance on a wide scale, it could endanger future treatment for mothers and infants."
Seble Kassaye, MD, instructor in infectious diseases and first generator of the study, will present the results Aug. 5 at the International AIDS Conference in Mexico City.
Last year, 420,000 babies were born HIV-positive, the large bulk of them to HIV-infected mothers in sub-Saharan Africa, according to figures from the United Nations Joint Programme on HIV/AIDS. The centerpiece of public health programs in the developing world to stop mother-to-child transmission of HIV ar both zidovudine (AZT) and nevirapine, which have been used as preventive tools in virtually 900,000 women and infants oecumenical. The drugs are relatively inexpensive and easy to administer, and nevirapine is typically granted as a single pill as the mother goes into task and as a liquid to the baby just after birth. Use of the do drugs reduces the chance of HIV contagion by half, to around 13 percent. However, not all HIV-infected women feature access to one or both of these drugs, especially in sub-Saharan Africa.
In addition, nevirapine has proven to be problematic. Previous studies have institute that as many as 69 per centum of HIV-positive mothers and as many as 80 percent of babies born infected, even after being given a single-dose of nevirapine without AZT, english hawthorn develop nevirapine-resistant strains of the virus.
In the latest subject area, the Stanford scientists set out to better understand this job.
They looked at a group of 32 HIV-positive pregnant women in Zimbabwe, where Katzenstein and his colleagues consume had on-going research and clinical programs in HIV/AIDS for more than a decade. The sub-Saharan African country has been difficult hit by the virus, with an estimated 17 to 18 percent of young adults estimated to be septic. Among significant women, some 20 per centum are thought to carry the virus.
In recent years, Zimbabwe has begun offering antiretroviral drugs to a limited number of infected patients, but at the time of the study, none of the women had been treated for their HIV. The only do drugs they received was the single cupid's itch of nevirapine when they went into labor, largely for the sake of their babies.
The researchers found that the drug persisted in the body for weeks, with more than half of the women having detectable levels in their blood inside two weeks after delivery. Two-thirds had measurable levels in their breast milk at two weeks, the researchers establish.
The thirster the do drugs remains in the scheme, the more likely it is to promote development of mutations in the virus. Although none of the HIV-infected women carried drug-resistant strains of the virus at the beginning of the study, at two months after birthing RNA tests showed a third of them had drug-resistant virus in their blood. Sixty-five percent had drug-resistant strains in their breast milk as substantially, with the potential to pass this on to their babies through breastfeeding, a common mode of viral transmission.
The mothers who were most likely to explicate resistant virus were those whose disease was more advanced as indicated by lower CD4 cell counts, the resistant cells targeted by HIV, Kassaye aforesaid. With advanced HIV contagion, these women are likely have more replicating virus, so they may be more prone to developing mutations that make the virus resistant to treatment, she said.
If these women had access to better, combination antiretroviral treatment to optimally suppress virus replication, they might be less likely to develop these hard-to-treat strains later, she said.
"It reinforces the pauperization to treat these women with combination therapy, thereby providing better prevention for the baby, while providing better handling for the mother," Kassaye said. "Public health efforts should preserve to expand combination therapy so that mothers and babies aren't left vulnerable to drug resistance."
Combination therapy is a ruffle of drugs that is more expensive - and thus less accessible - in the developing world. In the United States, HIV-positive women receive a highly effective form of combination therapy that has reduced transmission of HIV from mother to infants to less than 2 percent.
Other study authors at Stanford include Yvonne Maldonado, MD, professor of pediatrics; Elizabeth Johnston, PhD, research associate; Esther Lee, former graduate student; and Avi Shetty MD, former postdoctoral companion in pediatric infectious disease.
The work was fund by a grant from the Doris Duke Charitable Foundation and by the National Institutes of Health.
Stanford University Medical Center integrates enquiry, medical education Department and patient care at its trey institutions - Stanford University School of Medicine, Stanford Hospital & Clinics and Lucile Packard Children's Hospital at Stanford. For more than information, delight visit the Web site of the medical center's Office of Communication & Public Affairs at hypertext transfer protocol://mednews.stanford.edu.
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