New research finds that chemicals commonly found in non-stick cookware, microwave popcorn bags and other manufactured goods may make childhood vaccines less effective, perhaps making it easier for certain diseases to spread through the population.
A study published today in the Journal of the American Medical Association suggests that exposure to perfluorinated compounds, called PFCs, before and after birth may lower a child's ability to make disease-fighting antibodies for tetanus and diphtheria later in life.
Researchers studied nearly 600 children and their mothers from the Faroe Islands, a small nation in the North Atlantic between Iceland and Scotland. The researchers tested the levels of PFCs in the blood of the mothers when they were pregnant and in the children at age 5 and 7. The researchers also measured the children's immune system responses to vaccines for tetanus and diphtheria.
The study found that higher levels of PFCs in both mothers and children meant lower numbers of disease-fighting antibodies in the children. Mothers who had twice the level of PFC in their blood had children with a 40 percent decrease in the number of antibodies formed after getting the diphtheria vaccine. The 7-year-old children who had doubled PFC levels had nearly a 50 percent reduction in their antibody levels.
Study author Philippe Grandjean said very few chemicals are known to have such an effect on the body's immune system.
"The PFCs make the immune system more sluggish, so that it doesn't respond as vigorously against micro-organisms as it should," Grandjean said. "If vaccinations don't work, there may be an increased risk of epidemics."
Experts say a weaker vaccine can still be effective in fighting disease. But Paige Lawrence, director of the toxicology training program at the University of Rochester School of Medicine, said a vaccine's reduced effectiveness may affect people differently.
"For some people, a 40 percent reduction in immune response might not matter at all. For others, it could matter tremendously," Lawrence said. "What we can't do is predict who will be most affected. We don't have the ability to look at individuals and know who will get sick and who won't."
The study authors said the marine diet of Faroese people may have influenced the levels of PFCs in the children in the study, since the chemical is commonly found throughout the environment, even in polar bears that live far from pollution sources.
But exposure to the chemicals is also high in the United States. In 2004, the Centers for Disease Control and Prevention tested the blood of more than 2,000 Americans and found certain types of PFCs in nearly 98 percent of them.
And no wonder. PFCs are everywhere. They're found in Teflon cookware and some food wrappings, such as microwave popcorn bags and pizza boxes. Cleaning products, like the original Scotchgard, some shampoos, floor wax and carpet treatments are a common source of PFCs.
Industrial waste from some chemical plants has also dispersed PFCs in air and water, though the Environmental Protection Agency has been strengthening its regulation of the use of the chemicals in manufacturing in the past decade. In 2010, the agency announced new regulations requiring companies to submit notices when they intend to make PFCs. Eight companies are voluntarily phasing out the use of PFCs in their products as part of an EPA program.
"Certainly, this study begs to have further testing done on PFCs so, if in fact, subsequent studies demonstrate an impact on the immune system, this product is at least taken out of use going forward," said Dr. Ari Brown, co-author of "Baby 411" and a developmental pediatrician in in Austin, Texas.
This isn't the first study to find potential negative health effects of PFCs. A 2009 study linked exposure to the chemicals to potential delays in getting pregnant for a group of more than 1,200 women.
Lawrence said scientists need a better understanding of just how these chemicals affect humans.
"Often when we think about pollutants and how they affect our health, we think about important and scary diseases like cancer," Lawrence said. "That is very important, but as a society we often tend to overlook more subtle adverse effects, such as how a chemical affects our ability to fight infections."