Exposure to a group of chemicals widely used in consumer products reduces the effectiveness of childhood vaccinations, a new study suggests.
Children with the highest blood levels of perfluorinated compounds, or PFCs, had the weakest response to tetanus and diphtheria immunization shots, according to the study published this week in the Journal of the American Medical Association.
In particular, these kids produced far fewer infection-fighting antibodies in response to the shots. That suggests some children would be still vulnerable to tetanus and diphtheria even though they had been vaccinated.
"This evidence tells me that the immune system is very sensitive to PFCs," said the study's lead author, Philippe Grandjean of the University of Southern Denmark in Odense.
PFCs can be found in many products including non-stick cookware, stain-resistant clothing, water-repellant rain gear as well as food packaging. They are also extremely durable and persist in the environment for a long time. Most people carry detectable levels of PFCs in their bodies. Research has linked some of these chemicals to thyroid problems and other health concerns.
This latest study, the first to look at PFCs and vaccinations, is based on 587 children born in the Faroe Islands, located in the North Atlantic. PFC levels were measured in the children at age 5. Their mothers were tested when they were pregnant.
Dr. Grandjean, who is also a professor at Harvard University's school of public health in Boston, said a large portion of the PFCs found in these blood tests likely came from eating contaminated fish.
But he noted that the level of PFCs in the Faroe Islanders is about the same or even less than those in people in Europe and North America.
Many of these chemicals have been on the market for decades – long before governments introduced newer measures to protect consumers from potentially hazardous compounds. "This is a reminder that our system of chemical controls was not as good as it ought to have been," he commented.