Common chemicals may diminish children’s benefit from vaccines

A Harvard study reports that children exposed to chemicals in food packaging and textile products may have compromised immune systems.

A Harvard School of Public Health (HSPH) study published in the Journal of the American Medical Association suggests that exposure to prevalent household chemicals may lower children’s immune responses to vaccines. This is the first published study to find that exposure to perfluorinated compounds (PFCs)—chemicals commonly used in manufactured products such as nonstick cookware, waterproof clothing, and fast-food packaging, as well as in furniture, stain-resistant carpeting, and microwave popcorn bags—may thwart children’s ability to mount proper immune responses after they are vaccinated.

“Routine childhood immunizations are a mainstay of modern disease prevention,” said the study’s lead author, Philippe Grandjean, adjunct professor of environmental health, in a press release. “The negative impact on childhood vaccinations from PFCs should be viewed as a potential threat to public health.”

Grandjean and his HSPH colleagues studied a group of about 600 children born from 1999 to 2001 in the Faeroe Islands, north of Scotland—choosing that population specifically because most residents consume high levels of seafood and water known to have increased amounts of PFC. They found that those children whose PFC levels were twice as high as those of other subjects produced only half the amount of antibodies to diphtheria and tetanus as the children who tested lower for PFCs. By the age of seven, children with a twofold increase in PFC levels since birth were also two to four times more likely to show an immune response so low it was no longer clinically protective.

“We were surprised by the steep negative associations, which suggest that PFCs may be more toxic to the immune system than current dioxin exposures,” said Grandjean in a press release.

The Environmental Protection Agency has long been concerned with PFCs, and has linked the chemicals, which can remain in the body for several years, to various health-related issues such as birth defects and thyroid disorders. 

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