Lifetime PFAS exposures and childhood vaccine responses

Abstract

Background: Immunotoxicity has been selected as the critical effect of early-life exposures to perfluorinated alkylate substances (PFASs) in a 2020 draft opinion by the European Food Safety Authority. However, uncertainty prevails in regard to the most vulnerable age at exposure.Methods: A birth cohort of 490 children was recruited in the Faroe Islands in 2007-2009 and followed up with blood samples at ages 18 months, 5 and 9 years. PFAS concentrations were quantified in umbilical cord blood collected at birth and at postnatal examinations. Diphtheria and tetanus IgG antibody concentrations were quantified at ages 5 and 9 using ELISA assays. As blood samples from infancy were not available, we modeled serum-PFAS concentrations at ages 3 and 6 months using structural equations. We used linear regressions to examine PFAS associations with age-9 antibody concentrations allowing for sex-specific associations.Results: PFAS exposures were lower than in a previous Faroese birth cohort. In cross-sectional analyses at age 9, PFAS concentrations did not show any associations with tetanus or diphtheria antibodies. However, a doubling in the cord blood concentration of perfluorooctanoic acid (PFOA) was associated with a decrease in tetanus (12.6%; 95%CI: -22.1, -1.9) and diphtheria (16.3%; 95% CI: -28.2, -2.3) antibody concentrations. Tendencies were less clear at other ages and for other PFASs. A doubling of the modeled PFOA concentration at 3 months was associated with lower tetanus antibodies (20.8%; 95% CI: -35.0, -3.5%) at age 9. Weaker associations were observed for exposures at age 6 months. There was some indication of sex-specific associations that varied by antibody type.Conclusions; Early-life exposure to PFOA has the strongest impact on vaccine antibody concentrations in later childhood.