The authors explained that vaccine effectiveness relies on the proper functioning of the body's immune system, and that a link between PFC exposure and vaccine levels could also reflect a more general problem with immune system function.
"For this reason, the PFC-associated decreases in antibody concentrations may indicate the potential existence of immune system deficits beyond the protection against the two specific bacteria examined in this study," they wrote.
The new paper comes after December's release by an unrelated three-person team of scientists of a "probable link" finding between C8 and high blood pressure among pregnant women -- the first major conclusion of the C8 Science Panel's six-year study of the DuPont Co. chemical.
Panel members had also said they viewed evidence as "insufficient" to conclude chemical exposure was related to birth defects, pre-term births, low birth weight, miscarriages and stillbirths.
The panel's work is part of a class-action lawsuit settlement between DuPont and Mid-Ohio Valley residents whose water was contaminated with C8 by DuPont's nearby Washington Works plant.
C8 is another name for perfluorooctanoate acid, or PFOA. In West Virginia, DuPont has used C8 since the 1950s as a processing agent to make Teflon and other nonstick products, oil-resistant paper packaging and stain-resistant textiles.
DuPont and other companies have reduced their emissions and agreed on a voluntary phase-out of the chemical, but researchers are still concerned about a growing list of possible health effects and about the chemical's presence in consumer products, as well as continued pollution from waste disposal practices.
David Savitz, a Brown University scientist and panel member, said that the new Harvard study found "bigger effects than we're seeing at much higher exposure levels" than his group has so far pinpointed.
The C8 Science Panel has focused on potential health effects among Mid-Ohio Valley residents who, because of drinking water exposure to C8 and living near the DuPont plant, have far more C8 in their bodies than the average American.
Faeroe Islands children who were part of the Harvard study appear to have lower levels of PFCs in their blood than U.S. children, meaning the study results could be even more important for Americans, Savitz said.
"The biggest concern is not for these potential diseases, but whether this suggests a broader immune response," Savitz said. "That would suggest a greater and broader risk of infection and have a broader array of health consequences."
Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.