Preventing HIV Transmission from Mother to Child After Birth

Human Immunodeficiency Virus (HIV) transmission from infected mother to child is a major public health concern in many nations worldwide. Prophylactic treatment of mothers with anti-retroviral drugs is effective in preventing child infection during the birthing process. However, transmission can still occur during breast feeding, which happens to be recommended by the World Health Organization (WHO) to prevent infant mortality in offspring of HIV infected mothers in poorer nations. Thus, a double edged sword is formed. Breast feeding is recommended by the WHO to prevent infant death in developing countries, however, it can also facilitate HIV transmission from mother to child.

A new study published in The New England Journal of Medicine assessed three separate treatment strategies, two experimental and one control anti-retroviral regimen, for preventing maternal transmission of HIV to offspring.

The study recruited HIV-1 positive pregnant women in Lilongwe and Malawi who were 14 years of age or older, pregnant for 30 weeks or less, had a CD4 count above 250 cells/ml, hemoglobin of at least 7 g/dL, and lacked liver damage. They were excluded if any complications with pregnancy were present or had severe infections. Offspring also had to be at least 2 Kg when born to be eligible. All mothers received anti-retrovirals during labor and for 7 days after. Likewise all offspring received anti-retrovirals for 7 days after delivery.

Mothers were instructed to breast feed for 28 weeks and either they or their child received anti-retrovirals. The authors followed three separate groups of patients: Those that received only the 7 day treatment, mothers who received 28 weeks of ant-retrovirals, or offspring that received 28 weeks of anti-retrovirals. This allowed the authors to assess whether treating for 7 days, only the mothers for 28 weeks, or only the children for 28 weeks was the most efficient for preventing transmission from mother to child. The investigators removed offspring from the study who were HIV positive after 2 weeks and allowed them to get proper care. The population was then followed from weeks 2 to 28 to ensure any transmission detected was due to breast feeding.

The control treatment group had a calculated risk of HIV-1 infection of 5.7%, the maternal treated group risk was 2.9%, and 1.7% for the offspring treated group. Differences between the control group and the offspring, along with the maternal treated group, were statistically significant. Offspring and maternal treatment also prevented the rate of HIV infection or death at a greater extent than in the control group.

This study suggests that treating HIV positive mothers, or their children, for an extended period of time is more effective than short term prophylaxis. Such treatment, if employed in areas of the world where HIV prevalence is high, could dramatically reduce the number of new cases per year.

References:

Chasela CS, et. al. Maternal or Infant Antiretroviral Drugs to Reduce HIV-1 Transmission. N Engl J Med. 2010 Jun 17;362(24):2271-81.