In HIV-exposed and HIV-infected infants aged six to 15 months
breastfeeding significantly lowered the risks of getting malaria according to
Neil Vora and colleagues in a prospective study of infants in Tororo, a high
malaria transmission rural area in south eastern Uganda, published in the
advance online edition of the Journal of
Acquired Immune Deficiency Syndromes.
However the researchers found that breastfeeding was not
protective against malaria in HIV-unexposed and HIV-infected children of 15-24
months of age.
Co-trimoxazole prophylaxis appeared to significantly reduce
the risks of malaria when comparing HIV-unexposed infants not taking
co-trimoxazole to HIV-infected or exposed infants taking co-trimoxazole.
Breastfeeding is recognised as being one of the most practical
and cost-effective ways of providing the best nourishment to infants, of
boosting the baby’s immunity by providing protection from infectious disease
and reducing diarrhoeal diseases as well as respiratory illnesses. Further
evidence has shown that stopping breastfeeding early increases morbidity and
mortality rates among children born to HIV-infected mothers.
The World Health Organization (WHO) now recommends that
HIV-infected mothers exclusively breastfeed their infants who are HIV-uninfected
or of unknown status “for the first six months of life, introducing appropriate
complementary foods thereafter, and to continue breastfeeding for the first 12
months of life.”
WHO also recommends that all HIV-infected and mothers who
are nursing take co-trimoxazole prophylaxis
(also known as trimethoprim-sulfamethoxazole or TS, Bactrim, or Septra);
for infants born to HIV-infected mothers co-trimoxazole prophylaxis should
start at six weeks of age. For children who are breastfeeding prophylaxis
should continue until breastfeeding has stopped and HIV negative status is
confirmed.
Co-trimoxazole prophylaxis is known to reduce malaria
incidence in both HIV-infected adults and children. In vitro studies have shown
that breast milk proteins contain antimalarial properties.
Little clinical evidence exists about the effects of
breastfeeding on the incidence of malaria in children. Data that does exist
does not consider the mother’s HIV status. The high incidence of malaria and
HIV in young children across sub-Saharan Africa
highlights the importance of understanding the association between
breastfeeding and malaria, particularly in the context of the new breastfeeding
guidelines.
A cohort of 99 HIV-unexposed children, 202 HIV-exposed
children and 45 HIV-infected children enrolled between August 2007 and April
2008 were followed prospectively. All children were given insecticide-treated
bednets. Co-trimoxazole prophylaxis was given to both HIV-infected and HIV-exposed
infants. A malaria diagnosis was made by the presence of fever and a positive
blood smear. Monthly questionnaires were used to determine when breastfeeding
stopped.
This study was part of a larger cohort study designed to
compare the effectiveness of two different artemisinin-based therapies for
treating malaria and to measure the protective efficacy of cotrimoxazole
prophylaxis against malaria in HIV-exposed and HIV-infected children.
The median age at enrollment for HIV-exposed children was significantly
lower than for HIV-unexposed or HIV-infected, 3.7 (IQR:2.4-6.6), 5.6
(IQR:3.5-7.4) and 4.9 (IQR:3.0-8.3) months, respectively. HIV-infected children
were more likely to live in town compared to HIV-unexposed and exposed children
(36% compared to 21%, p=0.03).
The authors found that the link between breastfeeding and
malaria varied in relation to age and use of cotrimoxazole.
Insufficient data were available for children HIV-unexposed between
the ages of six-15 months and not breastfeeding to evaluate an association
between breastfeeding and the risk of malaria; the majority of children in this
category breastfed for 15 months or more.
No significant difference in the incidence of malaria was
seen in this category of children (HIV-unexposed) aged 15-24 months whether
they breastfed or not (7.5 compared to 6.67 episodes for each person-year,
p=0.21). Following policy guidelines these children did not get co-trimoxazole
prophylaxis.
Breastfeeding, however, was associated with a significantly
lower malaria incidence rate in HIV-exposed children taking co-trimoxazole aged
between 6-15 months (1.36 compared to 2.44 for each person-year p=0.008). Since
most children in this category stopped breastfeeding before 15 months of age,
in accordance with guidelines, there was insufficient data to evaluate the
association between breastfeeding and malaria.
HIV-infected children taking cotrimoxazole showed a greater
variation of when breastfeeding stopped compared to the other groups. In those
aged between 6-15 months breastfeeding was associated with a significantly
lower incidence of malaria (1.13 compared
to 3.76 for each person year, p=0.002) whereas in those aged 15-24 months there
was no significant difference between those who breastfed and those who did
not. Why breastfeeding is protective in the younger age group and not the older
is uncertain.
After controlling for age, breastfeeding status and place of
residence the risk for malaria in children taking cotrimoxazole prophylaxis
(HIV-infected and HIV-exposed) was significantly lower than in those not taking
prophylaxis (HIV-unifected) RR =0.42 95% CI: 0.34-0.52, p<0.001.
The authors also found, unlike in adults, no association
between HIV and the risk of malaria in children aged 6-15 months of age and
taking cotrimoxazole prophylaxis. They suggest this is because of an immature immune
system; infants have still to develop partial immunity characteristic of adults
after repeated exposure.
Limitations, note the authors, include:
- Sample
sizes were not based on testing the hypothesis that breastfeeding reduces
the risk of malaria, so they were unable to analyse all possible
associations when disaggregating by age and HIV status.
- The
observational nature of the study meant that analyses were not adjusted
for confounding factors, including socio-economic or nutritional status.
So breast-feeding could have been a surrogate for time spent outside, or
under an insecticide-treated bednet as well as for the nutritional status
of the infants. All these factors that would affect the risk of malaria.
The authors conclude that “breastfeeding was protective
against malaria in children born to HIV-infected mothers, but this effect faded
with age.”
They stress the need for further research to confirm their
findings as well as explain how breastfeeding is protective against malaria.
Based on their findings, they recommend that “HIV-infected
mothers should be counselled about the importance of breastfeeding and
co-trimoxazole prophylaxis to protect their children and themselves against
malaria.”