Lowering HIV transmission risk from breastfeeding with antiretroviral treatment

Now they can breastfeed with less risk. An international consortium of researchers, including a team from the IRD, recently showed that by taking an antiretroviral treatment up to the sixth month of breastfeeding mothers can halve the probability of contaminating their child in comparison with standard treatment recommended in the previous WHO (World Health Organization) protocol guidelines. This new approach reduces the risk of HIV transmission from 9.5 to 5.4%. These highly encouraging results prompted WHO to revise their guidelines on prophylaxis during breastfeeding.

In low-income countries, 1.4 million women are living with HIV, the virus that causes AIDS. If no prevention measures are taken, the risk for future mothers of transmitting HIV to their child in utero, during delivery or when breastfeeding is 35%. By following WHO recommendations hitherto in force, they could already cut the probability of contamination by taking an antiretroviral drug called zidovudine during pregnancy, followed by a single dose of nevirapine, another antiretroviral, at onset of labour. The study entitled Kesho Bora ("a better future" in Swahili) recently showed that it is just as possible to breastfeed with lower risk.

Halving the risk

The international research consortium involved, which includes an IRD team, puts forward a new approach that cuts the risk of postnatal transmission by half compared with the one recommended in previous international guidelines. The research team ran a clinical trial between 2005 and 2008 among 800 women in Burkina Faso, Kenya and South Africa, with the aim of comparing the efficacy of their new protocol with that of the then standard form of prophylaxis. The scientists administered to a group of patients, between the 28^th and 36^th week and up to the sixth month of breastfeeding, a combination of three antiretrovirals: zidovudine, lamivudine and lopinavir/ritonavir. With this preventive triple antiretroviral prophylaxis, only 5.4% of infants at 12 months of age proved to be infected, compared with 9.5% in the standard zidovudine and single-dose nevirapine group. The new combination turned out to be even more effective in women with a high viral load.

WHO guidelines revised

Breastfeeding therefore is not as risky as it was. This amazing breakthrough, as WHO considers it, prompted the organization to revise its guidelines. Since the beginning of 2010, WHO has been recommending continuation of the prophylaxis throughout the breastfeeding period. Two new options are now open to expectant mothers. They can either take zidovudine during pregnancy, then give their child nevirapine daily until weaning; or follow the triple-preventive prophylaxis described by the Kesho Bora study during pregnancy, then continue until they stop breastfeeding. WHO considers that if started from the 14^th week of pregnancy, these new treatment protocols will in the long run reduce the risk of HIV transmission to less than 5%.

A difficult choice

In 2009, 370 000 new infections by mother-to-child contamination occurred, bringing the global total of children under 15 years living with HIV to 2.5 million. In many countries, mothers are faced with a painful dilemma. Abandoning breastfeeding effectively reduces the risk of mother-child transmission to only 2%. But this also deprives their infant of maternal antibodies, which build their immune system, and of a unique nutritional resource. The child is exposed to the risk of diarrhea or malnutrition induced by feeding with artificial milk and insufficient drinking-quality water. Moreover the mothers themselves become open to forms of stigmatization in their entourage. And without a food aid programme that would distribute free artificial milk free-of-charge, that means committing expenditure from the family's economic resources for at least a year.

Although antiretrovirals are still expensive and to date not all patients eligible for these treatments yet have access to them, the Kesho Bora study shows the importance of providing these medications to mothers carrying HIV or to their children. These new measures will contribute towards achieving the Millennium Development Goals for reduction of child mortality by 2015.

Notes:

These investigations were conducted jointly with WHO researchers in Geneva (coordinating centre), The Centre Muraz at Bobo-Dioulasso, Burkina Faso; Kenyatta National Hospital, Nairobi and the International Centre for Reproductive Health, Mombasa, Kenya; KwaZulu Natal University, Africa Center for Health and Population Studies at Durban, South Africa; CDC and NIH, United States; and the University of Montpellier I. The research received financial backing from the ANRS (French Agence Nationale de Recherches sur le Sida), the EDCTP (European and Developing Countries Clinical Trials Partnership), the Thrasher Research Fund, the CDC of Atlanta, NIH and WHO.

Until the beginning of 2010 WHO recommended the administration of a single dose of zidovudine twice a day during pregnancy, then a single dose of nevirapine at labour onset followed by a one-week treatment for the newborn.