PCBs, DDT Exposure Impacts Infant Response to TB Vaccine

Babies exposed to chemicals such as polychlorinated biphenyls (PCBs) and DDT show weakened responses to the tuberculosis (TB) vaccine, according to a new study.

PCBs and DDE are passed from mother to child through breastfeeding, and can have serious implications for babies as the early development of the immune system is so intricate. Researchers examined blood samples and immune responses from 516 healthy mother and infant pairs living in an area of eastern Slovakia heavily contaminated with environmental toxins. Each baby was given the tuberculosis vaccine four days after birth. Six months later, the babies were measured for their antibody responses.

Infants who had the highest concentrations of PCBs in their blood had the lowest antibody count for fighting TB. Babies in the 75^th percentile of PCB concentrations had 37% lower antibodies for the TB vaccine when compared with PCB concentrations in the 25th percentile.

DDE presence (the main breakdown product of DDT) also reduced the babies’ responses to the TB vaccine, though not as strongly as PCBs. The study showed those with traces of both chemicals fared the worst.

PCBs were banned in the U.S. in 1979, even so, nearly all people have detectable concentrations in their blood. DDT is also banned in the U.S. but some countries still use it to control the spread of malaria.

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