Maternal HIV Infection and Antibody Responses in Uninfected Infants

To the Editor: In their study of maternal human immunodeficiency virus (HIV) infection and antibody responses against vaccine-preventable diseases in uninfected infants in South Africa,¹ Dr Jones and colleagues found that antenatal HIV exposure was associated with a greater magnitude of change in antibody responses between birth and 16 weeks in those exposed to HIV than in the unexposed group. The study supports the view that antenatal exposure to HIV does not compromise the ability to respond to vaccine antigens. Jones et al recognized important limitations of their study design (ie, uncertainty about maternal vaccinations) that might have contributed to the observed differences. However, they did not consider that the differences may partly result from breastfeeding. All of the unexposed group were breastfed at birth and 42% at 16 weeks of age, while none of the exposed infants were. Breastfeeding modulates the serum immune response to vaccine antigens^2- 3 and may even have unfavorable effects on antibody responses.⁴ Breastfeeding could explain the observed lesser magnitude of change in antibody responses in the unexposed infants.