摘要：Objectives. We assessed the association between exposure to an educational intervention that emphasized safer breastfeeding practices and postnatal HIV transmission among 437 HIV-positive mothers in Zimbabwe, 365 of whom did not know their infection status. Methods. Mothers were tested for HIV and were encouraged—but not required—to learn their HIV status. Intervention exposure was assessed by a questionnaire, Turnbull methods were used to estimate postnatal HIV transmission, and multivariate Cox proportional hazard models were constructed to assess the association between intervention exposure and postnatal HIV transmission. Results. Cumulative postnatal HIV transmission was 8.2%; each additional intervention contact was associated with a 38% reduction in postnatal HIV transmission. HIV-positive mothers who were exposed to both print and video materials were 79% less likely to infect their infants compared with mothers who had no exposure. These findings were similar for mothers who did not know their HIV status. Conclusions. The promotion of exclusive breastfeeding has the potential to reduce postnatal HIV transmission among women who do not know their HIV status, and child survival and HIV prevention programs should support this practice. Each year, an estimated 700 000 children are infected with HIV by their mothers, 1 and at least 40% of these transmissions occur during breastfeeding. 2 – 3 The vast majority of HIV-infected children live in sub-Saharan Africa, where universal and prolonged breast-feeding protects children against diarrhea and other infections and contributes to birth spacing (i.e., intervals between pregnancies). 4 – 6 Hence, the transmission of HIV through breastfeeding has created one of the most challenging dilemmas of the HIV pandemic and has contributed to reduced support for breastfeeding in some areas where there is a high prevalence of HIV. 7 International guidelines currently state that HIV-positive mothers should avoid all breast-feeding when replacement feeding is acceptable, feasible, affordable, sustainable, and safe. Otherwise, HIV-positive mothers are advised to breastfeed exclusively during the first months of life and to stop breastfeeding as soon as the conditions for replacement feeding are met. 8 Counselors should provide information on the risks and benefits of exclusive breastfeeding and replacement feeding so that HIV-positive mothers can make fully informed decisions. 9 We developed an education and counseling intervention to fully inform women about infant feeding in the context of HIV. We then implemented it within an ongoing postpartum vitamin A supplementation trial, Zimbabwe Vitamen A for Mothers and Babies Trial, hereafter “ZVITAMBO,” in Harare, Zimbabwe. As part of the trial, participating mothers were tested for HIV within 96 hours of delivering their babies and were encouraged—but not required—to learn their HIV status. The intervention promoted exclusive breastfeeding to mothers who were HIV-negative, mothers who were HIV-positive and chose to breastfeed, and mothers who chose not to learn their HIV status. We evaluated the association between the mothers’ exposure to this intervention and their HIV-related knowledge, infant-feeding practices, postnatal HIV transmission, and child mortality. In 2005, we reported that women who enrolled in the trial after the intervention was implemented were more knowledgeable about HIV and were 8.4 times more likely to practice exclusive breastfeeding compared with women who enrolled in the trial before the intervention began. 10 Furthermore, exclusive breastfeeding for at least 3 months was associated with significantly lower postnatal transmission and higher HIV-free survival compared with partial breastfeeding (i.e., animal milks or solid foods in addition to breast-milk). 11 Our findings were consistent with previous reports from South Africa. 12 , 13 In this study, we examined the association between the amount of exposure mothers had to the educational intervention and their infants’ risk for postnatal HIV transmission or death. The analysis examined HIV-positive women whose infants were alive and were HIV polymerase chain reaction (PCR)–negative at 6 weeks, which put them at risk for postnatal HIV transmission. We hypothesized that exposure to the intervention would be inversely associated with HIV transmission and that this association would be attenuated after we adjusted for breastfeeding exclusivity. Previous studies on breastfeeding and HIV have included only HIV-infected women who made feeding decisions after learning their HIV status. The ZVITAMBO is unique in that both HIV-negative and HIV-positive women were enrolled and the majority declined to learn their test results. 10 Thus, our analysis reflects the potential impact of a public health intervention that promotes exclusive breast-feeding in settings where HIV prevalence is high, yet the majority of mothers do not know their HIV status. These conditions are common throughout Africa. 1
