HIV Transmission Through Breastfeeding

A Study in Malawi

Miotti, Paolo G. MD
Taha, Taha E. T. MD
Kumwenda, Newton I. PhD
Broadhead, Robert FRCP
Mtimavalye, Laban A. R. FRCOG
Van der Hoeven, Len RN
Chiphangwi, John D. FRCOG
Liomba, George FRCPath
Biggar, Robert J. MD

Author Affiliations: Department of Epidemiology, Johns Hopkins School of Hygiene and Public Health, Baltimore, Md (Drs Miotti, Taha, and Kumwenda, and Ms Van der Hoeven); Malawi College of Medicine, Blantyre, Malawi (Drs Broadhead, Mtimavalye, Chiphangwi, and Liomba); and the National Cancer Institute, National Institutes of Health, Bethesda, Md (Dr Biggar). Dr Miotti is currently with the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Md.

Corresponding Author and Reprints: Paolo G. Miotti, MD, NIAID, Division of AIDS, Room 4109, 6700-B Rockledge Dr, MSC 7626, Bethesda, MD 20892-7626 (e-mail: [email protected]).

JAMA: The Journal of the American Medical Association 282(8):p 744-749, August 25, 1999.

Context

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.

Design

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

Setting

Postnatal clinic of tertiary care hospital, Blantyre, Malawi.

Participants

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

Main Outcome Measure

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.

JAMA.1999;282:744-749