Packaging weakens children's vaccines
Food packaging chemicals can weaken the ability of vaccination jabs to protect young children, research suggests.
A study linked exposure in the womb or in the first years of life to lower immunity to tetanus and diphtheria.
The chemicals, known as perfluorinated compounds (PFCs) are widely used in manufacturing and food packaging.
Scientists analysed data on 587 children born in the Faroe Islands between 1999 and 2001.
The children were tested for immune responses to tetanus and diphtheria vaccinations at the ages of five and seven years.
Researchers also measured PFC levels in the blood of mothers and five-year-olds.
The findings, published today in the Journal Of The American Medical Association, showed that PFC exposure was associated with fewer numbers of antibodies, an essential part of the immune system.
It also increased the chances of children having antibody levels insufficient to provide long-term protection.
Doubling the concentrations of three major PFCs led to a halving of antibody levels in children at age seven.
Study leader Dr Philippe Grandjean, from the Harvard School of Public Health in Boston, US, said: "Routine childhood immunisations are a mainstay of modern disease prevention.
"The negative impact on childhood vaccinations from PFCs should be viewed as a potential threat to public health."
Exposure to two common PFCs before birth had a negative impact on diphtheria vaccinations.
A two-fold increase in levels of one, perfluorooctane sulfonic acid (PFOS), reduced antibody counts by 39pc in five-year-olds.
"If the associations are causal, the clinical importance of our findings is therefore that PFC exposure may increase a child's risk for not being protected against diphtheria and tetanus, despite a full schedule of vaccinations," the authors wrote.
The trend may reflect a more general impact on the immune system's ability to fight infection, said the scientists.
Alastair Hay, Professor of Environmental Toxicology at the University of Leeds, said the research "must be an alert for all health and environment authorities".