The Public Health Risks of PFAS-related Immunotoxicity Are Real

Our collective experience and conversations about the global pandemic elevated social knowledge about the immune system to a level never seen before. Whether talking about protecting the elderly or immunocompromised or the effectiveness of vaccines, we are all now much more aware of the importance of having a healthy immune system to protect us from myriad threats. For many, this experience has highlighted that a functional immune system is important not just for protecting us as individuals, but also for protecting the entire population. 

Unfortunately, some chemicals can interfere with the immune system - including PFAS (per- and polyfluoroalkyl substances, also known as toxic “forever chemicals”). PFAS are a class of thousands of man-made chemicals that pose numerous health and environmental concerns.

In 2016 the National Toxicology Program concluded that PFOA and PFOS - the two most highly studied PFAS - are “presumed to be an immune hazard to humans.” Given the importance of a healthy functioning immune system to both personal and public health, it is imperative we take steps to limit our exposure to immunotoxicants like PFAS. Yet there are several examples where PFAS associated immunotoxicity has not been properly acknowledged and accounted for in recent regulatory and clinical decision making contexts. 

In collaboration with other experts, our new commentary explores how PFAS associated immunotoxicity can be better addressed to provide greater public health protections.

What do my blood PFAS levels mean? 

Virtually all of us have some level of PFAS in our blood. So what does that mean for our health?

People from highly contaminated communities have been asking their health care providers this very question. Yet, despite a growing list of health concerns related to PFAS exposure, clinicians have had little guidance for counseling patients hoping to interpret their blood PFAS levels. In 2021 a committee was formed by the National Academies of Science Engineering and Medicine (NASEM) to try to sort this out. 

The committee recommended that anyone with blood PFAS levels above certain thresholds should receive some additional medical monitoring above the normal standard of care. The goal of this recommendation is to identify potential concerns early so that preventative measures can be taken. Despite the committee’s finding that the immune system is harmed by PFAS exposure, they made no recommendations on additional care, precautions, or treatment for people with elevated PFAS blood levels related to immune system health or functioning. 

In particular, there is strong evidence indicating that exposure to PFAS causes decreased antibody response to vaccines. A vaccine is less effective if a person does not have a sufficient antibody response to it. This is particularly concerning given the global pandemic that we are all emerging from, thanks in large part to widespread vaccination campaigns. A decreased antibody response is also an indication of general immunosuppression, which means that not only is a person’s ability to fight communicable diseases like colds and COVID diminished, but also their body’s ability to protect itself from other threats like cancer. Despite that in other contexts there is established clinical guidance for patients with immunosuppression, these existing resources were not referred to or incorporated by the NASEM committee. We recommend that the NASEM guidance be revisited and strengthened to provide such guidance as appropriate for PFAS impacted individuals and communities. 

Other issues

Briefly, other issues we identify and discuss in our commentary include:

• EPA’s failure to quantify immunotoxicity harms when it performed an economic analysis in support of the proposed national drinking water regulations for six PFAS. This resulted in an underestimate in the health benefit of treating drinking water to remove PFAS;
• The lack of required functional immunotoxicity and developmental immunotoxicity tests for new chemicals entering the marketplace;
• Inconsistent approaches in risk assessment to account for lack of immunotoxicity data for PFAS that are likely to be immunotoxic due to their similarity to well-studied, immunotoxic PFAS and; 
• The frequent use of poorly defined labels such as “mechanistic,” “subclinical,” or “biomarker” to diminish the importance of observed immunotoxic effects. 

What can be done?

The public health risks of PFAS-related immunotoxicity are real and our commentary outlines several recommendations to more fully account for and address these health harms in different decision making contexts. First, the importance of the observed immunotoxic effects of PFAS in humans must be acknowledged and not minimized as has been attempted in several recent reviews (see here and here). Second, we identified that more rigorous immunotoxicity testing is needed before chemicals like PFAS enter the marketplace. And when such data are available, they need to be more fully incorporated into decision making processes. Finally, people in highly polluted communities should be made aware of the potential for PFAS to harm their immune systems, as knowing this may influence behaviors they take to protect their health. Updated clinical guidance that provides recommendations related to immune system health are needed to improve the health and quality of life of PFAS impacted individuals and communities.