Three new University of Arizona-led studies are trying to determine if “forever chemicals” known as PFAS compounds increase the risk of contracting COVID-19 or weaken vaccines’ ability to protect against the disease.
The federally financed studies, now underway, are examining whether PFAS in blood serum can increase COVID-19 risk for firefighters, other first responders, health-care workers and others, including teachers, who hold what are considered essential jobs. Blood serum is the clear fluid left over in blood after potentially clotting materials are removed.
Underlying this research are previous scientific findings that PFAS at high enough concentrations in people have been documented to weaken immune systems’ resistance to disease. Research has also shown the PFAS compounds can suppress humans’ response to other vaccines.
One new study specifically targets the effects of PFAS on firefighters’ antibody response to COVID-19, said UA public health professor Jeff Burgess, lead researcher on all three studies.
In the other two studies, researchers will collect blood serum samples for PFAS as part of projects targeting COVID-19’s presence in various occupational groups, Burgess said.
The studies are financed by the Centers for Disease Control, the U.S. Agency for Toxic Substances Disease Registry, and the National Institute for Environmental Health Sciences.
“They’re trying to really understand the nature of the infection and the risk factors for it, and to understand the effectiveness of vaccinations at preventing COVID-19,” said Burgess, associate dean for research at UA’s Mel and Enid Zuckerman College of Public Health.
“Their main point is to analyze vaccine effectiveness,” Burgess said of the latter two studies.
Previous evidence led to new studies
The three studies would not have been financed without some reason to believe that PFAS exposures could affect COVID-19, he said.
“The information that’s out there is that PFAS exposures can in other infections, predominantly respiratory infections, can increase susceptibility to infection and also reduce immune response to vaccination,” Burgess said.
The CDC and the Agency for Toxic Substances and Disease Registry recognize these problems from past studies, the CDC told the Arizona Daily Star in an email.
“Because COVID-19 is a new public health concern, any and all work around understanding this virus is occurring in a very dynamic environment, where things change and evolve each day,” CDC said.
PFAS compounds are widely used chemical combinations, comprised of a chain of carbon and fluorine atoms linked together. Because the carbon-fluorine bond is one of the strongest known forms of chemical bonding, these chemicals do not degrade in the environment, says the National Institute of Environmental Health Sciences. That’s how they got the nickname “forever chemicals.”
How people are exposed to the chemicals
The highly mobile compounds have turned up regularly in drinking water systems in the Tucson area and nationally. Eighteen drinking water wells in Tucson Water’s system have been shut down due to PFAS contamination, and major parts of the utility’s central and south-side wellfields have PFAS contamination. Two Marana Water well systems have also been tainted by PFAS.
Two treatment plants aimed at removing PFAS and another chemical from well systems serving more than one-third of Marana’s water customers are scheduled to go online in late February or March.
A smaller, pilot cleanup effort by the Arizona Department of Environmental Quality to remove PFAS from water from Tucson Water’s central wellfield is scheduled to start in late spring or early summer 2021.
Various PFAS varieties have been detected in a wide variety of consumer products. They include nonstick and stain-resistant products, carpets, fabrics, food and cardboard packaging, pesticides and cosmetics, said Linda Birnbaum, a former director of the national environmental health science agency. She spoke at a media briefing given recently by the Environmental Working Group, an advocacy group battling to reduce PFAS use and contamination nationally.
“There are more than 200 categories for these chemicals” in which they’re used, said Birnbaum. “They are everywhere. There are over 9,000 of these chemicals that have been intentionally synthesized.
“You can ingest them from drinking water; food or dust. You can inhale them. You can also have dermal exposure in some compounds. Everyone in America has some PFAS in their body,” Birnbaum said.
UA focusing on firefighters, among others
Details of the UA’s PFAS studies:
- One called Arizona Heroes has enlisted 3,000 more than firefighters, first responders and other front-line workers in the state. About 2,000 of them didn’t have COVID-19 when the study started in June and still don’t. Another 1,000 participants either had COVID-19 when they joined the study or have since developed it.
The researchers are trying to enroll another 1,000 such workers who have contracted COVID-19 but haven’t been yet vaccinated.
Those not infected are tested weekly to see if they get infected and regularly provide blood samples to measure antibody levels. Once participants are vaccinated, researchers will keep testing them for COVID-19 and monitoring antibody blood levels.
About 800 of the front-line workers being studied include teachers and workers in food service, retail, child care, manufacturing, utilities and construction, said Karen Lutrick, an assistant UA food and medicine professor. The study’s cost is $7.7 million.
- A study called Recover, in which a CDC-financed, private company is supporting research at several sites nationally, including Tucson and the Miami, Florida, area.
So far about 2,000 people working in similar jobs to those studied in Arizona Heroes have been recruited at several sites for that study, which began in April 2020. Burgess couldn’t provide the study’s total cost.
- A study called Paces is collecting blood from 100 to 120 firefighters in the Tucson area and in Florida who have COVID-19 to determine PFAS levels. Costing nearly $405,000, the study began in September.
Firefighters can be at risk for incurring PFAS contamination because many have used PFAS-tainted firefighting foam on the job, particularly at military bases.
Harvard study found a link
So far, the one study to find a link between PFAS and COVID-19 was led in Denmark by researchers at Harvard University’s School of Public Health.
It examined blood plasma samples from 323 persons, ages 30 to 70, with known infections by SARS-CoV-2, the virus that causes COVID-19.
Two-thirds of the study participants had been hospitalized, and 16% were either put in intensive care or were deceased.
The study found blood samples containing elevated concentrations of a type of PFAS known as PFBA were associated with an increased risk of suffering a more severe course of COVID-19.
But because the study’s participants had generally low exposure levels to PFAS compounds, the question of PFAS-COVID-19 links needs to be studied in populations with elevated exposures, the study concluded. It was published in late 2020 in the journal PLOS One.
The PFBA compound, unlike most other PFAS compounds, can concentrate in peoples’ lungs, but “as far as we know,” all PFAS compounds are toxic to the immune system, said Harvard Professor Phillipe Grandjean, the study’s lead author.
The compounds found most commonly in Tucson-area drinking water have been PFOS and PFOA.
Grandjean said he hopes the studies led by Burgess will result in new findings, “as they can be very relevant to our understanding of COVID-19 and the mystery why some infected patients become very sick while others just get mild symptoms.
“It’s also important for us to appreciate that toxic chemicals do not necessarily cause poisoning but that they may interfere with body functions, including the immune system, and cause greater vulnerability to other disease, such as infections,” he said.
Research important for prevention
These UA studies are hugely important and very timely, said Jamie DeWitt, an East Carolina University researcher who has extensively studied PFAS health impacts.
Besides the knowledge that PFAS exposure can suppress vaccine resistance to infections in general, we also already know that such compounds are widespread in peoples’ bodies and those of animals tested in studies, DeWitt said.
“We also now are in the midst of a pandemic to a novel pathogen (COVID), so we have immune systems naïve to this pathogen and can ask real-time questions about infection rates and severity and how those correlate with internal PFAS blood concentrations,” said DeWitt, an associate professor of pharmacology and toxicology and principal investigator for a research lab that investigates PFAS impacts.
Benefits from such research are particularly important for prevention, she said.
“If a person lives in an area with known PFAS contamination and we know that PFAS increases the risk of COVID, this person can take greater cautions to avoid exposures,” DeWitt said.