Background:  The Kesho Bora (“A better future,” Swahili) study conducted at 5 sites in Africa recruited HIV-infected pregnant women to participate in either a randomized clinical trial (if CD4⁺ 200 to 500 cells/mm³) or a prospective cohort study (if not eligible for the clinical trial) to assess the efficacy of maternal antiretrovirals for prevention of mother-to-child HIV transmission (MTCT). We report HIV-free survival and cumulative risk of infection at age 12 months according to breastfeeding choice from the prospective cohort.

Methods:  From January 2005 to August 2006, women with CD4⁺ counts (cells/mm³) <200 or with symptomatic HIV disease initiated ART (zidovudine [ZDV]/lamivudine [3TC]/nevirapine [NVP]) from 34 to 36 weeks pregnancy and continued after delivery. Those with CD4⁺ >500 and asymptomatic received ZDV alone until delivery with single-dose NVP at delivery (short-course prophylaxis). All infants received single-dose NVP. Infant HIV infection status was assessed using real-time RNA polymerase chain reaction (RT-PCR).

Results:  We enrolled 249 women (120 on ART and 129 on short-course prophylaxis) gave birth to 239 live born, first-born infants; 15 infants had not reached 12 months by August 31, 2007; 15 infants were HIV-infected; and an additional 19 infants died. The 12-month cumulative incidence of HIV infection or death was 18% (95%CI 12 to 26%) for infants born to mothers with CD4⁺ <200 who received ART and 12% (7 to 18%) for infants born to mothers with CD4⁺ >500 who received short-course prophylaxis. Of the total, 231 infants had at least 1 RT-PCR result. Of 7 infants diagnosed with HIV between 6 weeks and 12 months, 5 were born to mothers on ART. The number of HIV infections, number at risk, and 12-month Kaplan-Meier life table HIV infection rates are given in the table.

# HIV infections/#at risk; cumulative life-table rate (95%CI)

Conclusions:  ART in pregnant and lactating women who require ART for their own health is effective in reducing MTCT. Identification of women in need of long-term ART and active referral to HIV treatment clinics should be promoted. The 1-year cumulative risk of infection when the mother has CD4⁺ >500 is low (6%) and the potential additional benefit of giving ART to these women for prevention of MTCT during pregnancy and lactation must be carefully weighed.