Vertical transmission through breastfeeding remains a major problem in limited resource countries. This session explored options for prevention of mother-to-child transmission through breastfeeding.

Maintenance of exclusive breastfeeding (EBF) through the first four months of life, Lusaka, Zambia. Kuhn presented results from a prospective, study nested study within a randomized trial. All women were encouraged to breastfeed exclusively until four months. Uptake of EBF was high: at monthly clinic visits >90% reported that no other substances except breast milk had been given since the prior visit. Cumulatively, 84% reported only EBF. The risk of HIV infection by four months among infants surviving HIV-free at six weeks was 4% (95% CI: 2.4-5.6) among those who reported EBF and 10% (95% CI: 4.7-15.7) among those who reported non-EBF (p=0.004). The findings indicate that in this setting high uptake of EBF can be achieved with a counseling intervention.

Triple antiretroviral therapy (ART) given to breastfeeding (BF) mothers with formula feeding (FF) for prevention of post-natal mother-to-child transmission, Rwanda. Arendt described the results of a study among HIV-1 infected women followed at four antenatal care sites in Kigali. All received NNRTI-based HAART starting after the second trimester of pregnancy. Women were given the choice between FF or BF with weaning at 6 months. The latter group continued ART until one month after the end of BF. Of 572 women were enrolled, 58% opted for FF while 42% for BF under ART. Of 431 children, 7(1.6%) were infected with HIV, only 1/176 (0.6%) through BF.  These findings suggest breastfeeding with ART can minimise HIV-1 infection in the baby while keeping the benefits of breastfeeding.

Treating mothers prophylactically with triple antiretroviral therapy during late pregnancy and six months of breastfeeding, Dar es Salaam, Tanzania. Kilewo presented data from an open-label, non-randomized, prospective study (MITRA PLUS). Women were treated with zidovudine (ZDV) + lamivudine (3TC) + nevirapine (NVP) during late pregnancy and breastfeeding (NVP was replaced by nelfinavir for mothers with adverse reactions on NVP). The infant received ZDV + 3TC for one week after birth. Treatment of the mothers was stopped at six months except for those who needed ART for their own health. Mothers were counselled on exclusive breastfeeding and encouraged to stop at six months. The cumulative proportion of HIV-1 infected infants was 4.1 % (95%CI 2.1%-6.0%) at 6 weeks and 5.0% (95%CI 3.2-7.0%) at six months. These findings were similar to a previous study (MITRA) where infants received therapy, instead of the mothers. In MITRA PLUS, women with late stage diseases would benefit more from therapy.

Coll presented information on the maternal and fetal safety of nevirapine-containing HAART regimens during pregnancy, Barcelona. A retrospective multicenter study including three university hospitals was carried out. A total of 311 women were identified as receiving HAART during pregnancy, 61% with NVP-containing regimens. A total of 21 toxic events occurred in 17 pregnant women on NVP-containing regimens, no events were observed in women without NVP (p <0.001). The incidence of toxicity in women on NVP-containing regimens was 8.9%. Adverse perinatal outcome was less frequent in women on NVP-containing regimens (30.9 vs. 40.8%; OR 0.65 (0.4-1.04), but the finding was not statistical significant (p=0.07). The use of NVP during pregnancy would need to weighed up in the context of the adverse events and the potential lower incidence of adverse perinatal outcome shown here.