Unfortunately, the complexity and cost of the PACTG 076 zidovudine regimen has restricted its applicability to resource-rich countries. The World Health Organization estimated that 3.2 million children were living with HIV infection at the end of 2002, the vast majority infected through MTCT. More than 90% of these perinatal infections occurred in resource-limited countries. The results of SAINT and of 6 other large, randomized, controlled clinical trials conducted in resource-limited countries since 1999 (4 of which involved breast-feeding populations) confirm that nearly 50% efficacy in reducing MTCT can be achieved with several short, simple, effective, and inexpensive antiretroviral prophylaxis regimens, including regimens of zidovudine alone, a combination of zidovudine and lamivudine, and single-dose nevirapine. Moreover, the SAINT data provide further evidence of the safety of the single-dose nevirapine and short-course zidovudine/lamivudine prophylaxis regimens; no serious drug-related adverse events were observed in the >1300 women and infants enrolled in the study.
Thus, the lack of an affordable, safe, and effective intervention can no longer be viewed as an insurmountable barrier to prevention of MTCT in resource-limited countries. However, in contrast to rapid and widespread implementation of programs to reduce MTCT in resource-rich countries, these effective short-course regimens have had slow uptake in resource-limited countries, and the momentum of the epidemic has continued unabated, with >800,000 infants newly infected during 2002 alone. Significant economic, social, and governmental barriers to implementation of MTCT prevention programs have existed in resource-limited countries. In addition, HIV transmission through breast-feeding remains a significant problem in countries where safe replacement feeding is not possible
As pharmaceutical companies have initiated programs to provide drugs for prevention of MTCT at greatly reduced or no cost to resource-limited countries, the cost of MTCT programs has become tied less to financing the purchase of the antiretroviral prophylactic regimen than to developing and supporting the mother-child health care infrastructure required for implementation of such programs, which has remained problematic for many resource-limited countries. The simple intrapartum/postpartum zidovudine/lamivudine and nevirapine prevention regimens studied in SAINT can be implemented even in settings in which women may have only limited antenatal care or present to the health care system for the first time in labor. Women must, however, be able to access the health care system to be able to receive such interventions, which may be difficult in rural settings, in which many deliveries occur at home with traditional birth attendants. There is a need for the development of innovative delivery systems for provision of preventive regimens in such settings