Childhood vaccinations are a staple of disease prevention. But a new study finds that when children are exposed to elevated levels of common industrial chemicals called perfluorinated compounds or PFCs, their immune systems become less responsive to routine vaccines, putting them at risk for serious illness.
PFCs are everywhere in the environment. The industrial compounds are used as water repellents in rain gear, cloth, carpeting, and food packaging. The chemicals are stable and extremely persistent. Almost everyone has a detectable level of PFCs in their body from exposure through clothing or food products, or from drinking PFC-contaminated drinking water.
Although the health effects of PFCs are still a poorly understood problem, a team of scientists has identified at least one very serious adverse effect on children's immune systems.
Doctor Phillipe Grandjean, at the Harvard School of Public Health in Massachusetts, and his colleagues found that children exposed to PFCs in the womb, and later exposed to elevated levels of the chemical in the environment, showed evidence of reduced immune protection against two diseases, tetanus and diphtheria.
Grandjean and his team determined the effectiveness of the childhood vaccines by measuring the concentration of blood-borne antibodies against the two illnesses in a group of vaccinated children.
Vaccines stimulate the body's production of antibodies, or protective proteins, by exposing the immune system to tiny, harmless amounts of a disease-causing microorganism. Later on, if the antibodies encounter that microbial invader in force, the protein sentries alert the immune system to the presence of disease-causing organisms and specialized cells are dispatched to destroy them.
Grandjean says many children in the study who had been exposed to high levels of PFCs showed very low concentrations of tetanus and diphtheria antibodies in their blood. “And some of these kids had such low concentrations that they were essentially unprotected by age seven, despite the fact that they had had four vaccinations by that time," he said.
Grandjean says these children were re-vaccinated, though it is uncertain how well the vaccines will protect them from tetanus and diptheria. And he says the evidence suggests their immune system deficits might create vulnerabilities to other disease organisms as well.
“I mean this is the mainstay of prevention. We want our kids to be vaccinated. But the problem is if the vaccines don’t work because the immune system has become sluggish because of pollution, then we have a problem," he said.
The study involved 587 children, born between 1999 and 2001, in the Faroe Islands, a country in the Norwegian Sea that lies between Scotland and Iceland. Researchers chose the Faroe Islands because the diet of residents is rich in seafood, which is known to contain high concentrations of PFCs.
Grandjean says pollution by perfluorinated compounds is a global problem in need of an international solution. He notes that while the U.S. has stopped manufacturing PFCs, the chemicals are now produced in countries like China and used in a variety of imported and American-made products.
An article by Phillipe Grandjean and colleagues on the reduced effectiveness of childhood vaccinations is published in the Journal of the American Medical Association.
