Food packaging and vaccines: Overexposure to a class of chemical compounds widely used in food packaging may make routinechildhood vaccinations less effective, according to a study in the Journal of the American Medical Association.

Researchers followed 656 children born in 1999 and 2000 at the National Hospital in the Faroe Islands (a self-governing Danish territory about halfway between Iceland and Scotland) from birth through 2008.

At several important ages, the researchers measured the mothers' and children's exposure to perfluorinated compounds (PFCs), a group of chemicals used for a range of industrial applications, including food packaging. Previous studies have linked PFCs to immune suppression in rodents.

The children received routine vaccinations against tetanus and diphtheria at age 5. The higher the blood levels of the most common PFCs at age 5, the weaker the immune response to those vaccinations - and thus the greater risk of the vaccines failing. A twofold increase in the concentration of perfluorooctanoic acid, a type of PFC, at age 5, for instance, was associated with more than double the risk of falling below the 'clinically protective' threshold of antibody response to the diphtheria vaccination.