Babies of HIV-positive mothers are twice as likely to become infected by the virus if they are given formula milk in addition to breast milk, and the risk rises eleven-fold if they are given solid foods, South African researchers have found.
Exactly why mixing breastfeeding with other foods increases the risk of HIV infection is still unknown, although there is growing evidence that proteins from milk or solids not from breast milk damage the mucosal lining of the intestinal tract, and facilitates entry by the HI virus.
The research, by a team at the Africa Centre for Health and Population Studies and University of KwaZulu-Natal, confirms that where mothers are unable to provide formula feeding safely, and sustainably, exclusive breastfeeding is the safest option. The research showed that with education and support from healthcare workers more than two-thirds of women were able exclusively to breastfeed their children — that is give no other fluids or foods — for at least three months, and about half up to six months.
A recent child survival study conducted by international researchers estimated that exclusive breastfeeding could prevent 13% of deaths among children under five born to HIV-positive mothers in high prevalence settings. This rises to 15% in areas with low levels of HIV.
However, even among exclusively breastfed babies there is a subgroup — infants with a low birth weight or whose mothers had CD4 counts of less than 200 — who are twice as likely to become infected with HIV from their mothers, and almost four times more likely to die within their first six months. The finding confirms the need to prioritise giving antiretrovirals to pregnant women in clinical need.
Repeated research has shown that breastfed babies in developing countries tend to have a greater chance of surviving the major childhood killer illnesses such as diarrhoea and malnutrition. But each year thousands of children are also infected with HIV through breastfeeding, especially in areas like South Africa, where the clade C strain of the virus predominates. Clade C appears to be more readily transmitted through breastmilk than clades A and B, which predominate in other parts of the world.
Professor Nigel Rollins, one of the leaders of the team, says that many doctors and nurses do not believe in the feasibility of exclusive breastfeeding and this message is transmitted to patients, who then feed their infants formula or solids.
‘In South Africa the number of new infections amongst young women is terrifying, and it is very possible that many women become infected after their first HIV test at antenatal clinics without realising it,†said Rollins. ‘These infants are at extremely high risk of contracting HIV. If exclusive breastfeeding is promoted for all mothers and infants then the risk of this unobserved and unrecognised transmission will be reduced and overall child survival will be improved.â€
The research, which was funded by the British-based Wellcome Trust, will be published in the latest edition of The Lancet this week, and has already led the World Health Organisation to adjust its infant feeding guidelines. The international agency now recommends exclusive breastfeeding for HIV-positive women for six months, unless certain strict criteria are met for exclusive formula feeding.
Snip for safety
Mass male circumcision may be on the way for South Africa after a decision by the World Health Organisation and UNAids to recommend access to the procedure because of ‘compelling evidence†of its benefits in preventing the spread of HIV. South Africa has a high prevalence, generalised heterosexual HIV epidemic and low levels of male circumcision. The two UN agencies suggest that in such situations governments should ‘consider urgently scaling up access to male circumcision servicesâ€.
Several studies, including one in South Africa, have found that male circumcision reduces the risk of heterosexual men contracting HIV by about 60%, but doesn’t remove it entirely. — Belinda Beresford