Exclusively Breastfed Babies Born To HIV Infected Mothers Have Lower Infection Risk

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Main Category: HIV / AIDS
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Article Date: 30 Mar 2007 - 8:00 PST

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A new study suggests that babies born to HIV infected mothers have lower HIV infection risk when fed exclusively on breast milk for at least six months than those who are raised on alternatives such as baby formula, animal milk or mixed breastfeeding.

This study concords with other reports that exclusive breastfeeding confers a significantly lower risk of HIV transmission compared with mixed breastfeeding. The study is published in the current issue of The Lancet.

The study authors, Hoosen Coovadia and Nigel Rollins from the University of Kwa-Zulu Natal, South Africa, and colleagues from the UK, are calling on UNICEF, WHO, and UNAIDS and other agencies to change their policy on breastfeeding versus alternative baby feeding in the developing world.

The current policy is that where it is safe to do so (for example facilities for water and bottle sterilizing exist), HIV-infected mothers should bottle feed their babies. Where it is not safe to bottle feed, then exclusive breastfeeding is recommended.

The study authors are suggesting this policy is changed in favour of exclusive breastfeeding.

The non-randomized study was conducted in 9 antenatal clinics in KwaZulu Natal, South Africa: seven rural, one semiurban, and one urban and included 2722 HIV-infected and uninfected pregnant women who were followed until the babies were at least 6 months old.

Every week the mothers were asked questions about what their babies were being fed on, and every month blood samples were taken from mothers and babies.

The researchers analyzed the HIV tranmission risk at various infant ages up to 6 months, and assessed the influence of other mother and child variables on the risk, such as mothers' immune system health and babies' birth weights.

The findings revealed that the HIV infection risk of an exclusively breastfed baby at the age of 6 months who was uninfected at 6 weeks was 4 per cent.

This figure is roughly in line with the findings from other studies in South Africa and Zimbabwe, although direct comparisons are difficult because they used different methods.

However, babies who had formula milk as well being breastfed, before or after 14 weeks old, were almost twice as likely to be infected as exclusively breastfed babies.

Moreover, breastfed babies who were also fed with solids were nearly 11 times more likely to become infected compared with exclusively breastfed babies.

While the study did not look into the causes of the increased risk, the authors speculated on what they might be.

One suggestion was that babies who are fed exclusively on breast milk develop a stronger lining in the mucosa of their intestines creating an effective barrier to HIV. Another suggestion was that women who exclusively breastfeed their babies tend to have fewer breast health problems such as mastitis and abscesses which are linked to higher levels of HIV in the breast milk.

Speculating on why the risk was so high for breastfed babies who were also fed on solids, the authors suggested that the large protein molecules in the solid food may weaken the cells in the gut, or change the way cell receptors work in the gut, allowing the HIV to breach its integrity.

The survival rate of breastfed babies was also influenced by the status of the mother's immune system.

Exclusively breastfed babies of mothers with CD4-cell counts below 200 per microlitre were twice as likely to become infected and nearly four times more likely to die before reaching the age of 6 months than babies whose mothers' CD4-cell count was above 500 per microlitre.

The authors argue that this makes a case for giving breastfeeding mothers with low CD4-cell counts priority for receiving retrovirals as early as possible to increase survival rates for themselves and their babies.

The study concludes with a key message for policy makers,"Early introduction of solid foods and animal milks increases HIV transmission risks compared with exclusive breastfeeding from birth. These data, together with evidence that exclusive breastfeeding can be supported in HIV-infected women, warrant revision of the present UNICEF, WHO, and UNAIDS infant feeding-guidelines that were last revised in 2000."

"Mother-to-child transmission of HIV-1 infection during exclusive breastfeeding in the first 6 months of life: an intervention cohort study."
Hoosen M Coovadia, Nigel C Rollins, Ruth M Bland, Kirsty Little, Anna Coutsoudis, Michael L Bennish and Marie-Louise Newell.
The Lancet 2007; 369:1107-1116
DOI:10.1016/S0140-6736(07)60283-9

Click here for full text of Article (free subscription required).

Click here for UNAIDS pages on Mother to Child HIV transmission.

Written by: Catharine Paddock
Writer: Medical News Today
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