Findings Offer Insights into Role of
Breastfeeding in Preventing Infant Death, HIV Infection in
Resource Poor Countries
In many poor countries, mothers with HIV face a stark choice:
to nurse their infants, and risk passing on HIV through their breast
milk — or to formula feed, and deprive their infants of much
of the natural immunity needed to protect against fatal diseases
of early infancy. Now, two studies supported by the National Institutes
of Health offer insights into preventing early death and HIV infection
among breastfeeding infants of mothers with HIV in these countries.
The studies were published online in the New England Journal
of Medicine and will appear in the publication’s print edition
on July 10.
One study was supported in large part by NIH, with additional
funding by the Centers for Disease Control and Prevention and the
United States Agency for International Development. That study
found no benefit for infants born to mothers with HIV from abrupt
cessation of breastfeeding after the first four months of life.
In addition, this study found no difference in HIV infection rates
or in death rates by age 2 among infants abruptly weaned off all
breast milk at four months versus those who breast fed until later
in infancy. In fact, for one group of infants, those infected with
HIV, abrupt cessation of breastfeeding resulted in an increased
The other study, co-sponsored by the NIH and the Centers for Disease
Control and Prevention, found that it was possible to greatly reduce
the risk of HIV infection in breast-feeding infants by treating
them with an extended anti-HIV regimen. The treatment consisted
of the anti HIV drug nevirapine, alone or in combination with the
drug zidovudine, during the first 14 weeks of life.
"In poor countries where sanitation is a problem, exclusive breastfeeding
appears to confer the greatest benefits to infant health and survival,
even in mothers with HIV" said Duane Alexander, M.D., director
of the Eunice Kennedy Shriver National Institute of Child Health
and Human Development (NICHD), the NIH institute that provided
much of the support for the two studies. "Extended treatment with
nevirapine greatly reduces the chances that infants will be infected
with HIV through breast milk. The National Institutes of Health
is now sponsoring additional studies to determine the most effective
treatments to prevent the spread of HIV through breast milk."
In the developed world, mothers with HIV forego breastfeeding
and formula feed their infants, said Lynne Mofenson, M.D., Chief
of NICHD’s Pediatric, Adolescent and Maternal AIDS Branch, and
the project officer for the two studies. But in many poor countries,
there are barriers to formula feeding. Sanitation is lacking, and
clean water to mix formula is often not available. Many families
have difficulty affording infant formula. They also have difficulty
providing enough wood or charcoal for cooking fires to boil water
needed for formula.
Formula fed infants also miss out on protective antibodies — passed
on through breast milk — needed to ward off the deadly infant
diseases prevalent in many parts of the world. Formula feeding,
also, may carry a social stigma for mothers. The practice is often
seen as a tacit acknowledgement that a woman has HIV.
"Formula feeding is a hardship in many poor countries," Dr. Mofenson
said. "So the finding that it doesn’t confer any apparent benefits
in resource poor settings — and may even be harmful — has
The first of the two studies was conducted by Louise Kuhn, Mailman
School of Public Health, Columbia University, New York, and colleagues
from the Boston University School of Public Health, University
of Zambia, and other institutions.
The study was conducted in Lusaka, Zambia. The researchers enrolled
958 women with HIV and their infants. The women consented to be
randomly assigned to one of two groups. In the first, or intervention,
group, 481 women were counseled to exclusively breastfeed their
infants for four months, not offering any formula or other liquids.
The women were advised to stop all breastfeeding when their infants
were four months old. The women were also provided with formula
and instructed in how to safely prepare it. In the second, or control,
group, the women were advised to continue breastfeeding for as
long as they chose to. Infants were tested for HIV at birth, and
then periodically throughout the study, until they were 24 months
In the intervention group, 69 percent of infants had stopped breastfeeding
by 5 months of age. Children in the control group stopped breastfeeding
at a range of ages, between 5 and 24 months of age. Only 7 percent
of children in the control group had stopped breastfeeding by 5
months of age and 66 percent were still breastfeeding at 12 months
The researchers found no significant differences in survival between
the two groups. In the intervention group, 76.1 percent had survived
to 24 months of age, versus 75.4 percent in the control group.
Among infants who were still breastfeeding and uninfected at 4
months, there was also no significant difference in HIV-free survival
by 24 months (83.9 percent in the intervention group, versus 80.7
percent in the control group.)
Breastfeeding appeared to improve survival among infants who were
infected with HIV. Children in the intervention group who were
infected with HIV at or before 4 months of age and still alive
at 4 months of age had higher death rates by 24 months than did
their counterparts in the control group (73.6 percent versus 54.8
percent). Causes of death were predominantly diarrheal and respiratory
diseases, but also included malaria, malnutrition, measles, and
The researchers were surprised to find that the proportion of
new HIV infections between 4 and 24 months were not significantly
different between the two groups despite differences in the time
breastfeeding was stopped: 6.2 percent in the intervention group
and 8.8 percent in controls. The researchers theorized that the
chances of transmitting the virus may increase as a result of the
weaning process. The breast swelling and infection (mastitis) that
occurs when breastfeeding is sharply reduced may increase the likelihood
that the virus will be transmitted in the few feedings that remain.
The second study, conducted in Blantyre, Malawi, was led by Taha
E. Taha, of The Johns Hopkins University and Newton Kumwenda, of
the University of Malawi College of Medicine. Among the study’s
other authors were Dr. Michael Thigpen, of the CDC, and Dr. Mofenson.
In a study of 3,016 infants who did not have HIV at birth, the
researchers compared two extended regimens of nevirapine (NVP)
to the country’s standard treatment: a single dose of NVP given
to the mother during labor and to the infant at birth, with daily
doses of zidovudine (ZDV) given to the infant during the first
week of life.
The infants were assigned at random to one of three groups. The
control group received the standard treatment. The next group (the
extended NVP group) received the standard treatment plus NVP from
day 8 through the 14th week of life. The final group (the extended
NVP+ZDV group) received the standard treatment plus NVP and ZDV
from day 8 through 14 weeks.
When they were 9 months old, 10.6 percent of infants in the standard
treatment group had acquired HIV. By comparison, 5.2 percent in
the extended NVP group were infected and 6.4 percent in the extended
NVP+ZDV group were infected, corresponding to a 51 percent and
40 percent decrease in HIV infection, respectively. The difference
in HIV infection between the two extended treatment groups was
not statistically significant.
Infants in the NVP+ZDV group were more likely than infants in
the other groups to experience neutropenia, a deficiency of a certain
type of an infection-fighting cell. People with neutropenia may
be more susceptible to infection.
The study authors concluded that providing anti-HIV drugs to breastfeeding
infants is a practical and effective way to reduce HIV infection.
They noted that additional studies are needed to determine whether
it was safe to provide anti-HIV drugs to infants for the duration
Dr. Mofenson said that one NIH-supported study, now in progress,
was investigating whether anti HIV drugs could be safely given
to breastfeeding infants for the first six months of life. Another
NIH effort, now in the planning phase, will compare the effectiveness
of infant nevirapine given to breastfeeding infants for the entire
duration of breastfeeding, to the effectiveness of providing combination
anti-HIV therapy to breastfeeding mothers.
The NICHD sponsors research on development, before and after birth;
maternal, child, and family health; reproductive biology and population
issues; and medical rehabilitation. For more information, visit
the Institute’s Web site at http://www.nichd.nih.gov/.
The National Institutes of Health (NIH) — The Nation's
Medical Research Agency — includes 27 Institutes and
Centers and is a component of the U.S. Department of Health and
Human Services. It is the primary federal agency for conducting
and supporting basic, clinical and translational medical research,
and it investigates the causes, treatments, and cures for both
common and rare diseases. For more information about NIH and
its programs, visit www.nih.gov.