needed to quantify the risk of HIV transmission during vaginal delivery and to evaluate the efficacy of vaginal lavage in prevention of HIV transmission.

The most effective means of preventing perinatal transmission from HIV-infected mothers may be the administration of antiviral therapy such as Zidovudine (AZT) to the mother during pregnancy, labor, and delivery and then to the newborn during the first weeks of life. Data from a clinical trial involving 364 births to HIV-positive women showed a 67.5 percent reduction in the risk of HIV transmission attributable to AZT therapy (Centers for Disease Control, 1994). Efforts are now currently in progress to define the minimum dosage schedule for AZT in pregnancy. The trial results led the U.S. Public Health Service to issue new interim recommendations for care of pregnant women who meet the protocol eligibility criteria (Centers for Disease Control, 1994). However, there are several reasons why the therapeutic regimen in the trial (Protocol 076) will not be applicable to women in sub-Saharan countries. The main obstacle is the cost of the drug and sophisticated clinical equipment. Another obstacle is the requirement that babies be bottle fed with costly infant formula. Several studies are now under way to discover whether the trial results can be translated into a preventive strategy that can be used in developing countries, using either a shorter course of AZT treatment around the time of delivery or a lower dose of AZT (Cohen, 1995).

Vitamin A, dubbed ''the anti-infective vitamin" as early as the 1920s, is currently under investigation as an alternative method to reduce vertical transmission. Several recent studies that have evaluated the impact of vitamin A on vertical transmission of HIV give reason for optimism that vitamin A can inexpensively and easily reduce the risk of vertical transmission. In a 2-year study of 338 HIV-positive mothers in Malawi, Semba et al. (1994) found that women with higher serum vitamin A transmitted HIV to their children significantly less often than their vitamin A-deficient counterparts. The results were dramatic: 32.4 percent of women in the most deficient group transmitted HIV, while only 7.2 percent of women in the group with the highest serum vitamin A did so. Unfortunately, the research was nonexperimental, and it is possible that other nutritional or behavioral factors associated with serum vitamin A (such as general nutrition) played a significant role.

Other studies have proposed that the usefulness of vitamin A is as a preventative measure for morbidity associated with HIV/AIDS in children, rather than an inhibitor of HIV transmission per se. This hypothesis posits that vitamin A serves to enhance the immune system, thus reducing the severity of opportunistic infections or the duration of specific illnesses, rather than the likelihood of infection per se. A randomized, placebo-controlled study of 118 children of HIV-infected women in Durban, Natal, found that all children showed improvements in morbidity (measured in child-months of ill health) with vitamin A supplementation and that children who were themselves HIV infected showed particular improvement for diarrhea-related illness (Coutsoudis et al., 1995). A recent review of the effectiveness of vitamin A supplementation in the control of morbidity



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement