No benefit of early cessation of breastfeeding in the Zambia Exclusive Breastfeeding Study (ZEBS)

Polly Clayden, HIV I-Base

Discussion around formula feeding and breastfeeding had a high profile at this conference. Several studies looked at the risk benefits of feeding modes in various African settings.

Many guidelines and programmes recommend that HIV-positive women in resource poor settings who breastfeed, should end earlier than HIV-negative women. This is intended to reduce transmission, while preserving benefits of breastfeeding for the infants.

In an oral presentation Moses Sinkala presented findings from the Zambia Exclusive Breastfeeding Study (ZEBS) to evaluate whether or not there is a benefit with stopping breastfeeding abruptly at 4 months. [1]

In this study, 958 HIV-positive women and their infants were recruited, given single-dose nevirapine, and randomised after the infants were born into two groups. Women in group A stopped breastfeeding abruptly at 4 months, and those in group B continued breastfeeding for the duration of the mother’s informed choice. Exclusive breastfeeding (EBF) was promoted in both groups and 80.6% reported EBF at 4 months.

Transmission rates at 4 months were 10.1% vs 4.0% in non-EBF vs EBF infants (p=0.002). HR for increased transmission was 3.4 (95% CI, 1.7 to 7.2).

The median CD4 count of mothers across both groups was 329 cells/mm3 (IQR 207 to 471 cells/mm3). Mother and infant pairs were followed for 24 months; there was follow up for 85% of participants.

The investigators found that there was no significant difference in HIV-free survival between the two groups. With regard to uninfected infant survival at 4 months they reported: 17% of 329 infants in group A and 19% of 331 infants in group B had HIV infection or had died by 24 months (p= 0.21).

For the 153 infants who were HIV-positive by 4 months, there was a significant benefit for continued breastfeeding:  mortality by 12 months was 57% in group A compared to 29% in group B (p= 0.01).

In group A, 65% mothers reported stopping all breastfeeding by 4 months. In group B, the median duration of breastfeeding was 16 months. Among asymptomatic mothers with higher CD4 counts (>350 cells/mm3), there was a trend towards better infant outcomes with longer breastfeeding (p= 0.06).

The investigators concluded: “Our results caution against early cessation of breastfeeding for HIV-infected women living in low-resource settings. In our study, stopping breastfeeding at 4 months resulted in less than anticipated reduction of HIV transmission, a benefit that was offset by increased mortality among uninfected infants.” They noted that for HIV-positive infants in this study, continuing breastfeeding was beneficial.


  1. Sinkala M, Kuhn L , Kankasa C et al. No benefit of early cessation of breastfeeding at 4 Months on HIV-free Survival of Infants Born to HIV-infected mothers in Zambia: The Zambia Exclusive Breastfeeding Study. 14th CROI, 25-28 February 2007, Los Angeles. Oral abstract LB 74.

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