What are the health effects of PFAS?

Statement on Potential Intersection between PFAS Exposure and COVID-19:

CDC/ATSDR understands that many of the communities we are engaged with are concerned about how PFAS exposure may affect their risk of COVID-19 infection. We agree that this is an important question.

CDC/ATSDR recognizes that exposure to high levels of PFAS may impact the immune system. A National Toxicology Program review found that exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) is an immune hazard to humans based on a high level of evidence that PFOA and PFOS suppressed the antibody response from animals and a moderate level of evidence from studies in humans (NTP, 2016). More research is needed to understand how PFAS exposure may affect illness from COVID-19.

NTP (National Toxicology Program). 2016. Monograph on Immunotoxicity Associated with Exposure to Perfluorooctanoic acid (PFOA) and Perfluorooctane Sulfonate (PFOS).

African American pregnant mother and her daughter.

A large number of studies have examined possible relationships between levels of per- and polyfluoroalkyl substances (PFAS) in blood and harmful health effects in people. However, not all of these studies involved the same groups of people, the same type of exposure, or the same PFAS. These different studies therefore reported a variety of health outcomes. Research involving humans suggests that high levels of certain PFAS may lead to the following:


Increased cholesterol levels


Decreased vaccine response in children


Changes in liver enzymes

 Infant birth weights

Increased risk of high blood pressure or pre-eclampsia in pregnant women

Infant birth weights

Small decreases in infant birth weights

Cancer ribbon

Increased risk of kidney or testicular cancer

At this time, scientists are still learning about the health effects of exposures to mixtures of different PFAS.

One way to learn about whether PFAS will harm people is to do studies on lab animals.

  • Most animal studies have tested doses of PFAS that are higher than the doses people experience from environmental exposure.
  • These animal studies have found that PFAS can cause damage to the liver and the immune system.
  • PFAS have also caused low birth weight, birth defects, delayed development, and newborn deaths in lab animals.

Humans and animals react differently to PFAS, and not all effects observed in animals may occur in humans. Scientists have ways to estimate how the exposure and effects in animals compare to what they would be in humans.

Additional research may change our understanding of the relationship between exposure to PFAS and human health effects.