is more effective than zidovudine alone. These and other trials have led the World Health Organization to endorse the use of single-dose nevirapine prophylaxis in many developing world settings as a cost-effective way of reducing mother-to-child transmission. However, in the United States the Ugandan study was deemed flawed and as of 2006 the FDA has not approved of such nevirapine prophylaxis. However, supporters of HIVNET 012 experiment argued that the flaws in this experiment were largely due to bureaucratic incompetence, while the findings regarding the safety and efficacy of single-dose nevirapine from this study were scientifically solid and too important to discard. Moreover, it was argued that holding African researchers who operated under resource-poor situations to the same moral and procedural standards to their Western counterparts was unrealistic, and would further marginalize African researchers' role in the science community and impede the progress of African science. Another clinical trial, Using Nevirapine to Prevent Mother-to-Child HIV Transmission During Breastfeeding, was completed in September 2013. A major concern with this approach is that NNRTI resistance mutations are commonly observed in both mothers and infants after single-dose nevirapine, and may compromise the response to future NNRTI-containing regimens. A short course of maternal Lamivudine/zidovudine is recommended by the U.S. Public Health Service Task Force to reduce this risk. Adverse effects The most common adverse effect of nevirapine is the development of mild or moderate rash (13%). Severe or life-threatening skin reactions have been observed in 1.5% of patients, including Stevens–Johnson syndrome, toxic epidermal necrolysis and hypersensitivity. Nevirapine may cause severe or life-threatening liver toxicity, usually emerging in the first six weeks of treatment. In 2000, the U.S. Food and Drug Administration issued a black box warning on nevirapine, warning that it could cause life-threatening liver toxicity and skin reactions. Unacceptably high risk of serious liver symptoms in certain patient groups (women with CD4 count >250 and men >400) has led the U.S. DHHS to recommend the restriction of nevirapine use to those at lower risk, unless the benefit to the patient clearly outweighs the risk; although in the 2NN study which found these CD4 limits, the effect was seen only in patients recruited from Thailand. More recent studies on the use of Nevirapine in people with higher CD4 cell counts have come to the following conclusion: Treatment-experienced patients who start NVP-based combination therapy with low pre–ART and high current CD4 cell counts and an