Jan. 24, 2012 -- Routine vaccines may not work as well in children with elevated blood levels of chemicals called PFCs (perfluorinated compounds), according to a new study.
PFCs are widely found in consumer goods such as food packaging, stain-resistant carpeting, and other products.
In the new study, researchers looked at PFC levels in children's blood and their antibody responses, crucial to produce immunity.
As PFCs levels rose, the antibody response declined. "The immune system may not be as responsive as we want it to be," says researcher Philippe Grandjean, MD, DMSc, adjunct professor of environmental health at the Harvard School of Public Health in Boston. "It may become sluggish because of the PFCs."
His study is published in the Journal of the American Medical Association.
The study was funded by the National Institutes of Health and other governmental bodies in the U.S. and in Denmark. One co-author is a civil service employee at Statens Serum Institut, a government-owned vaccine maker in Denmark.
Taking exception to the study is Gilbert Ross, MD, medical director of the American Council on Science and Health, a nonprofit funded by corporations, organizations, and individuals. Ross calls the new research ''absolute junk."
PFCs and Vaccines: Study Details
In recent years, scientists have focused on potential health hazards linked with the chemicals, found in a wide variety of goods as well as in house dust. Some research has linked PFC exposure to lower birth weight and to higher cholesterol, for instance.
Previous studies in animals have found that their immune systems are highly sensitive to a common kind of PFC known as PFOAs (perfluorooctanoic acid), says Grandjean, who is also a professor and chair of environmental medicine at the University of Southern Denmark, Odense.
Grandjean and his colleagues focused on children's antibody responses to diphtheria and tetanus vaccines.
The vaccines are routinely given to children and teens. Tetanus or lockjaw can cause painful muscles spasms. Diphtheria can lead to breathing problems, heart failure, and paralysis and is potentially fatal.
Grandjean's team studied 656 children born from 1999 to 2001 at National Hospital in the Faroe Islands, northwest of Scotland. They took blood samples from the mothers at week 32 of their pregnancies. They took blood samples from the children at ages 5 and 7.
At the seven-year mark, 464 children were still involved in the study.
The researchers evaluated PFC levels and the levels of antibodies.
The most common PFCs found were PFOS (perfluorooctane sulfonic acid) and PFOA.
The higher the level of PFCs in the mother's blood, the less the child's ability to produce antibodies later, Grandjean found.
"The most distinct effect was found in the 7-year-old children," Grandjean says. If the PFC levels doubled at age 5, it could triple the risk the vaccine didn't work at age 7, he says.
"A study like this has to be repeated," Grandjean tells WebMD. The study finds a link or association. It does not prove cause and effect.
It is not a reason to skip routine vaccines, Grandjean tells WebMD. "To avoid getting shots would put kids in an even worse situation."
PFCs & Vaccines: Implications for U.S. Children?
The new study is one of the first to examine the link in people, says Olga Naidenko, PhD, a senior scientist at the Environmental Working Group, an advocacy organization. She reviewed the study findings for WebMD but was not involved in the study.
Even though the study was done in the Faroe Islands, she says, "I would feel comfortable saying this study has direct implications for U.S. children's health."
As Grandjean notes in the report, some data find that U.S. children may have higher blood levels of PFCs than adults and may have higher levels than the Faroese children.
Exactly how the PFCs may interfere with antibody responses is not known. Naidenko says the PFCs could be directly toxic to immune system cells. Or she says they may disrupt the cell-to-cell communication needed to produce the antibody response.
PFCs & Vaccines: Industry Input
A spokesman for DuPont, which makes products with PFCs, could not be reached for comment.
Marie Francis, a spokeswoman for the American Chemistry Council, an industry group, tells WebMD that the organization is reviewing the study. It needs to be replicated, she says.
“It is important for consumers to know that our companies, working with the EPA, have made marked progress towards advancing new chemistries that are substitutes for the older chemicals evaluated in this study. These new fluoro chemistries have an improved environmental and toxicological profile while continuing to offer consumer benefits,” Francis says.
In an emailed statement, Ross of the American Council on Science and Health says the study is "nonsensical."
"It appears to represent this group's attempt to link PFCs to some adverse health effect, " he writes. He notes that no one has found an increased risk of tetanus or diphtheria among even those with high levels of PFCs.
Ross says the study has ''no clinical significance whatsoever."
While funding for the council does include industry monies, Ross says that "less than 3% of the budget" comes from corporations that produce PFC-containing goods.
Lowering PFC Exposure
It's somewhat unclear where the chemicals found in the children’s blood come from, Grandjean says.
For that reason, "any advice and guidance on protection against PFCs are associated with some uncertainty," he writes in a background summary of his work.
Even so, he recommends avoiding:
- Microwave popcorn
- Furniture and carpet treated with stain repellents
- Shoes and clothing treated with stain repellents
- Lubricants for skis and ski boards, unless labels say they are PFC-free
PFCs are also found in common household dust, he says. Frequent vacuuming may help.