HIV transmission through breastfeeding: a study in Malawi.
BACKGROUND
Understanding the risk of human immunodeficiency virus (HIV) transmission through breastfeeding is essential for advising HIV-infected mothers and formulating public health policy recommendations.


OBJECTIVE
To measure the frequency, timing, and risk factors of HIV transmission through breast milk.


METHODS
Prospective cohort study conducted between 1994 and 1997, with follow-up of infants through 24 months of age.


METHODS
Postnatal clinic of tertiary care hospital, Blantyre, Malawi.


METHODS
A total of 672 infants (HIV-negative at birth) born to HIV-infected women who had not received antiretroviral drugs during or after pregnancy.


METHODS
Incidence of HIV in breastfed infants by age and maternal and infant risk factors for HIV transmission, using proportional hazard models to derive risk ratios (RRs) and 95% confidence intervals (CIs).


RESULTS
Forty-seven children became HIV-infected while breastfeeding but none after breastfeeding had stopped. The cumulative infection rate while breastfeeding, from month 1 to the end of months 5, 11,17, and 23, was 3.5%, 7.0%, 8.9%, and 10.3%, respectively. Incidence per month was 0.7% during age 1 to 5 months, 0.6% during age 6 to 11 months, and 0.3% during age 12 to 17 months (P = .01 for trend). The only factors significantly associated with low risk of postnatal HIV transmission in a multivariate model were high maternal parity (RR, 0.23; 95% CI, 0.09-0.56) and older maternal age (RR, 0.44; 95% CI, 0.23-0.84).


CONCLUSIONS
Our data suggest that the risk of HIV infection is highest in the early months of breastfeeding, which should be considered in formulating breastfeeding policy recommendations.
Miotti
P G
PG
Department of Epidemiology, Johns Hopkins School of Hygiene and Public Health, Baltimore, MD, USA. pm122m@nih.gov
Taha
T E
TE
Kumwenda
N I
NI
Broadhead
R
R
Mtimavalye
L A
LA
Van der Hoeven
L
L
Chiphangwi
J D
JD
Liomba
G
G
Biggar
R J
RJ
D001942:Breast Feeding / Q000009:adverse effects / Q000706:statistics & numerical data; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000706:statistics & numerical data; D008295:Malawi; D016012:Poisson Distribution; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012044:Regression Analysis; D012306:Risk; D012307:Risk Factors; D014886:Weaning