The exposure of children to chemicals used in food packaging can weaken the ability of vaccination jabs to protect young children, a recent report has suggested.

The study linked the use of perfluorinated compounds (PFCs) with the lower antibody response to routine childhood immunisations; it also found that exposure in the womb or in the first years of life lowered immunity to tetanus and diphtheria.

Study leader Philippe Grandjean from Harvard School of Public Health, US, said: "The negative impact on childhood vaccinations from PFCs should be viewed as a potential threat to public health."

Researchers analysed data from 587 children born in the Faroe Islands between 1999 and 2001, who were tested for immune responses to tetanus and diphtheria vaccinations at the ages of five and seven years.

The team, which also measured PFC levels in the blood of mothers and five-year-olds, found that PFC exposure was associated with fewer numbers of antibodies and increased the chances of children having antibody levels insufficient to provide long-term protection.

Doubling the concentrations of three major PFCs halved antibody levels in children at the age of seven, the researchers said.

The report published in Journal of the American Medical Association (JAMA) stated that exposure to two common PFCs before birth had a negative impact on diphtheria vaccinations.

The study also noticed a two-fold increase in levels of one perfluorooctane sulfonic acid (PFOS) reduced antibody counts in five-year-olds by 39%.