Q&A with Dr Tim Farley on the "Kesho Bora" study - HIV and infant feeding
Dr Tim Farley is a Scientist with WHO's Department of Reproductive Health and Research. For the past several years, he has been the Project Leader of the "Kesho Bora" study, which means "a better future" in Swahili. The study, led by WHO, in partnership with the French National Agency for Research on AIDS and Viral Hepatitis (ANRS), US Centers for Disease Control and Prevention (CDC) and Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) of the National Institutes of Health, offers new insights and new hope for preventing HIV infection and death among infants in settings where many mothers with HIV infection breastfeed.
On 22 July, the Kesho Bora study findings were presented at the International AIDS Society Conference on HIV Pathogenesis, Treatment & Prevention in Cape Town, South Africa. The key findings were as follows:
- Giving a combination of three antiretroviral drugs (zidovudine, lamivudine and lopinavir/ritonavir) to pregnant mothers with HIV infection and CD4 counts between 200-500 cells/mm3 from the last trimester, through delivery and six months of breastfeeding reduces the risk of transmitting HIV to the baby and improves survival compared with babies of mothers with HIV who are given the current WHO-recommended short-course ARV regimen;
- There is no increase in side-effects for the mothers or their babies associated with the triple-ARV regimen; and
- The biggest benefits in terms of HIV-free survival are among babies born to mothers with a CD4 count of between 200 and 350 cells/mm3.
This approach offers new hope for mothers with HIV infection who cannot safely feed their babies with infant formula or other replacement foods. These findings will be considered by WHO experts, together with other recent data on the use of ARVs to reduce HIV transmission during pregnancy and breastfeeding, when guidelines are updated later this year.
Below, Dr Farley answers some questions on HIV and infant feeding and the findings of the Kesho Bora study.
Q. What is the risk of a mother passing HIV to her child during breastfeeding?
A. Around one in six (15%) babies of women with HIV who are born uninfected become infected during breastfeeding if nothing is done (i.e. their mothers are not given ARVs, not offered infant feeding counselling, mothers not given infant formula, etc).
Q. Why do women in developing countries with HIV infection breastfeed?
A. Replacement feeding with infant formula is often regarded as a sign that a mother has HIV infection, so avoiding breastfeeding can sometimes result in stigma from neighbours and family. Replacement feeding is expensive, difficult to prepare safely in resource-limited settings, requires a regular supply of formula, clean water and heating facilities. WHO recommends replacement feeding for HIV+ women when it is acceptable (socially welcome), feasible (facilities and help are available to prepare formula), affordable (formula can be purchased for six months), sustainable (feeding can be sustained for six months) and safe (formula is prepared with safe water and in hygienic conditions). When these conditions are not met, WHO recommends exclusive breastfeeding for six months.
Q. Shouldn't all pregnant women with HIV infection be given combination ARVs, no matter what their stage of disease?
A. A woman with very early stage of HIV infection only has a low risk of transmitting HIV to her infant, particularly during breastfeeding (<1% when her CD4 count is above 500 cells/mm3). The picture is very different for women with advanced stage HIV disease (CD4 count below 200 cells/mm3) who require combination ARVs for their own health, which also reduces the risk of HIV transmission during pregnancy, delivery and breastfeeding. The Kesho Bora trial was conducted among women with intermediate stage HIV disease (CD4 count between 200-500 cells/mm3), for whom the best option has so far been unclear. The study showed that starting combination ARV drugs in pregnancy and continuing during breastfeeding appears to be safe, lowers the risk of transmission by 42% and the risk of HIV transmission or death by 36%. The absolute reduction in risk of transmission was greatest For women with CD4 counts between 200-350 cells/mm3, among whom the 12-month transmission rate was reduced from 11% to 6%. Although there are still uncertainties, it is likely that the benefits for this group of taking combination ARVs to prevent HIV transmission outweigh the risks. That being said, it is important to note that , at present, we do not know the long-term safety for the mother of starting and stopping combination ARVs when the drugs are not yet required for the mother's own health.
Q. What are the risks for the mother?
A. Some potential risks of taking ARVs include toxicity of the drug (causing damage to the mother's blood and liver) and the risk of the HIV virus developing resistance to the ARVs if not taken adequately (i.e. if the mother does not take the pills as prescribed). We do not yet have a complete picture of the impact on HIV disease progression of stopping ARVs after several months, once she has completely stopped breastfeeding her baby. Mothers who require ARVs for their own health must continue the treatment and the benefits outweigh any drug toxicity. But in mothers who do not yet require treatment for their own health it is currently unclear whether it is better to stop the ARVs once breastfeeding has stopped and restart when required. Further follow-up of mothers in the Kesho Bora study will provide important information on this issue next year.
Q. How much would it cost to give combination ARVs to all pregnant women with intermediate-stage HIV disease?
A. The cost of nine months of combination ARVs as used in the Kesho Bora study is about $450 for each woman treated. This compares with about $50 for the WHO-recommended short-course regimen. However, the cost of drugs is but a small component of the cost of screening, providing counselling and supporting pregnant women with HIV infection and their babies. About 25% of pregnant women with HIV require treatment for their own health. About another 25% of pregnant women with HIV have early stage disease, for whom the WHO-recommended short-course regimen is very effective. It is the remaining 50% of pregnant women with HIV - those with intermediate stage disease - who would benefit most from taking the regimen used in the Kesho Bora study.