Kids with more PFAS chemicals in their blood seem to have weaker responses to vaccines, and even very low levels — like 1.3 to 1.5 nanograms per milliliter — might be enough to cause this. That’s way lower than what safety rules usually consider risky.

What we've found so far is that higher levels of PFAS in children may be linked to weaker vaccine antibody responses. The evidence we've reviewed leans toward this pattern, even at very low exposure levels. Our analysis of the available research shows that children with more PFAS in their blood tend to have reduced immune responses after vaccination [1]. This includes common childhood vaccines, and the effect appears to happen at concentrations as low as 1.3 to 1.5 nanograms per milliliter [1]. These levels are much lower than those typically flagged as a concern by current safety standards, which suggests that even minimal exposure might matter for immune function [1]. We based this on 33 supporting assertions from the scientific literature, with no studies found that contradict this link [1]. While the number of studies is limited in this analysis, the consistency of the findings is notable. Still, we recognize that our understanding is incomplete and could change as more data becomes available. We do not yet know exactly how PFAS affects the immune system, or whether this reduced antibody response leads to more infections or less protection from disease in real-world settings. But what we can say is that the body of evidence we’ve reviewed so far points to a potential concern for children’s immune health. Practical takeaway: If you’re concerned about PFAS exposure, it may be worth considering ways to reduce it—like avoiding non-stick cookware, cutting back on packaged foods, and using filtered water—especially during early childhood when immune development is critical.