Read the full article by Lauren Brown, senior scientist for Abt Associates (Bloomberg Law)

“Among the many questions surrounding the Covid-19 pandemic, this one might be the most crucial: Why are some individuals who have been infected harder hit than others? We know underlying conditions account for some disparities, but there’s variation in impact even among those with such conditions.

In the field of chemical risk assessment and toxicology, we have been asking ourselves if some of this differential response could be explained by an individual’s previous chemical exposure. The U.S. population is at risk for exposure to multiple, ubiquitous chemicals that are known to adversely impact the immune system, making it more difficult to fight off infections such as Covid. Among this class of chemicals are per- and polyfluoroalkyl substances (PFAS).

PFAS is a group of chemicals that have been referred to as ‘forever chemicals’ given that, once in the environment, they are present more or less in perpetuity. These man-made substances have a variety of uses in commercial products, firefighting foams, food packaging, and water and stain repellents.

Certain chemicals in this class have been evaluated by the country’s top toxicological research agency, the National Toxicology Program, and have been found to be directly associated with adverse effects on the immune system. Other researchers have found associations between PFAS and a wide range of serious health impacts, including reproductive, developmental, endocrine effects, and increased risk of some cancers.

While many questions still remain about the potential impact PFAS exposure can have on the immune system, a review of the existing literature offers some insight into how these chemicals may be exacerbating the effects of Covid, and suggests some additional areas of inquiry.

PFAS Impacts the Immune System’s Memory

The human immune system is comprised of two response mechanisms that defend the body against harmful invaders: innate immunity and acquired immunity. Innate immunity is your first line of defense against an infectious agent and confers broad, non-specific protection from various pathogens. Sneezing, coughing, and fever are part of your innate immune system.

The acquired immune system is made of a highly complex set of cells, receptors, and communication mechanisms that remember what pathogens your body has been exposed to in the past and how you fought them off. This allows for specific responses to be initiated in the body to respond quickly and efficiently when you’re re-exposed to these pathogens…”