Breastfeeding causes nearly 40 percent of all
pediatric HIV infections yet also prevents millions of
child deaths every year by protecting infants from diarrhea
and other infections. Finding ways to make breastfeeding
safer for infants of HIV-infected mothers has been an
urgent research priority.
A study conducted by the Johns Hopkins
Bloomberg School of Public
Health, the University of Zimbabwe and Harare
(Zimbabwe) City Health Department found that exclusive
breastfeeding substantially reduces the transmission of HIV
from mother to infant and infant death, compared with
partial breastfeeding. Infants who were introduced to solid
foods or animal milk within the first three months were at
four times greater risk of contracting HIV through
breastfeeding compared to those who were exclusively
breastfed. The study is published in the April 29 issue of
"International guidelines currently recommend that
HIV-infected mothers should avoid all breastfeeding, but
only if replacement feeding is acceptable, feasible,
affordable, sustainable and safe," said Jean Humphrey,
principal investigator of the ZVITAMBO Study Project and
associate professor with the
Department of International
Health at the Bloomberg School. "For the large majority
of African women, this isn't the case, and breastfeeding is
the only choice. Our findings indicate that for these
mothers, delaying introduction of all non-breast milk foods
will substantially reduce the risk of HIV and death for
The study was conducted among 14,000 pairs of mothers
and newborns who were part of the ZVITAMBO project, which
examined the effects of vitamin A supplementation in
Zimbabwe. From this group, the researchers followed 2,060
infants from birth to age 2 who were born to HIV-positive
mothers. Information about infant feeding was collected at
ages 6 weeks, 3 months and 6 months. All infants were
breastfed but were categorized as exclusive (breast milk
only), predominant (breast milk and nonmilk liquids) or
mixed (breast milk and animal milk or solids)
In their analysis, the researchers found that mixed
breastfeeding quadrupled mother-to-infant HIV transmission
and was associated with a three times greater risk of
transmission and death by age 6 months when compared to
exclusive breastfeeding. Predominant breastfeeding was
associated with a 2.6-fold increase in HIV transmission as
compared to exclusive breastfeeding.
"These findings suggest that early introduction of
animal milk and solid food conveys especially high risk,
but that even nonmilk liquids like water or juice are
likely to increase the risk of HIV transmission," said
Ellen Piwoz, a senior author of the paper, director of the
Center for Nutrition at the Academy for Educational
Development and adjunct assistant professor in the
Department of International Health at the Bloomberg School.
"Therefore, HIV-positive mothers who choose to breastfeed
should do so exclusively, and the more strictly they are
able to comply, the lower the risk of HIV or death will be
for their infants."
"Our findings underscore the importance of supporting
exclusive breastfeeding, particularly in areas of high HIV
prevalence where many women do not know their HIV status,
and amongst HIV-positive mothers who choose to breastfeed.
Early introduction of nonhuman milks and solid foods should
be strongly discouraged because it increases the risk of
HIV infection for babies of HIV-positive women and the risk
of diarrhea and respiratory infections for all babies,"
said Lawrence H. Moulton, the study's senior statistician
and professor in the Department of International Health at
the Bloomberg School.
The study was written by Peter J. Iliff, Ellen G.
Piwoz, Naume V. Tavengwa, Clare D. Zunguza, Edmore T.
Marinda, Kusum J. Nathoo, Lawrence H. Moulton, Brian J.
Ward, the ZVITAMBO study group and Jean H. Humphrey.
Funding was provided by the ZVITAMBO Study Project
through grants by the Canadian International Development
Agency, from the United States Agency for International
Development through a cooperative agreement with Johns
Hopkins University and through a grant from the Bill and
Melinda Gates Foundation. Additional funding was provided
by the Rockefeller Foundation and Support for Analysis and
Research in Africa.