Exposure to certain pollutants early in life may do lasting harm to the immune system by blocking its response to vaccinations, suggests a study from the Faroe Islands.
That archipelago, which lies in the North Atlantic between Scotland and Iceland, makes a unique laboratory for studying the health effects of chemicals called polychlorinated biphenyls (PCBs). The Faroese traditionally hunted pilot whales, and some still eat the animals' blubber, which is heavily contaminated with PCBs. Those organic pollutants linger for years in body fat and are passed from mother to child during pregnancy and through breast-feeding.
"Some Faroese have 100-fold higher exposures to PCBs than others," says Philippe Grandjean of the Harvard School of Public Health in Boston and the University of Southern Denmark in Odense.