Almost six months into the coronavirus pandemic, it’s already clear that environmental pollution is responsible for some portion of the hundreds of thousands of Covid-19 deaths around the world. Now scientists are trying to pinpoint how exactly industrial chemicals make people more susceptible to the coronavirus and how much of the blame for the devastation wrought by the new coronavirus should be laid at the feet of the industry that produces those chemicals.
The link between Covid-19 and air pollution is particularly strong. A study set to publish in July linked six air pollutants in 120 Chinese cities with cases of the viral disease. Researchers in Italy have also shown that long-term exposure to air pollution is “significantly correlated with cases of Covid-19” in up to 71 provinces in that country. And a study that used data from California, set to publish in Environmental Research in August, showed that the air pollutants PM2.5, PM 10, nitrogen dioxide, carbon monoxide, and sulfur dioxide were associated with coronavirus infections. The authors of that study concluded that reducing exposure to these pollutants “will contribute to defeating COVID-19.”
Scientists have even managed to measure the precise harm that a single microgram/cubic meter increase in air pollution has on a population, which, according to researchers from the Harvard T.H. Chan School of Public Health, is “an 8% increase in mortality from COVID-19.”
While alarming, these findings aren’t surprising, according to Linda Birnbaum, the former director of the National Institutes for Environmental Health Sciences and the National Toxicology Program, who stepped down last year. “Everything in our health is determined by our environment,” she said.
In addition to air pollutants, Birnbaum pointed to the potential for endocrine-disrupting chemicals to make people more vulnerable to Covid-19. Among them are BPA and its replacements; phthalates, which are found in makeup, nail polish, and plastics, particularly food packaging; and PFAS, a class of industrial contaminants most famously used to make Teflon and other nonstick products.
Low levels of all of these chemicals are linked with conditions that have been shown to make Covid-19 worse. Phthalates are associated with damage to lungs and obesity, as well as to diabetes, the second most common underlying condition in people who die of Covid-19, according to the Centers for Disease Control and Prevention. BPA, which is often added to food packaging and drink bottles, is also linked to obesity, as well as asthma and diabetes.
PFAS, which also interferes with the functioning of the endocrine system, has been shown to cause several underlying conditions that leave people more vulnerable to Covid-19. People with higher levels of PFAS in their bodies are more likely to gain weight and have a harder time losing it. The chemicals not only increase obesity risk in those exposed, but also in the granddaughters of women who were exposed. And PFAS is associated with asthma and hypertension, two other conditions that appear to worsen people’s chances of surviving Covid-19. PFAS causes kidney disease and elevates levels of cholesterol and other fats in the blood, which also increase the chances that people with Covid-19 will be hospitalized or need intensive care.
The vast majority of people who die of Covid-19 had at least one other illness before they got sick from the virus. Compared to people who didn’t have underlying conditions, patients who had kidney disease, diabetes, lung disease, and heart disease, among other conditions, are six times as likely to be hospitalized with Covid-19 and 12 times as likely to die, according to the most recent data from the CDC.
In addition to causing medical problems that make people more vulnerable to the coronavirus, several environmental contaminants, including PFAS, also directly weaken the body’s immune response. Studies have shown that in both adults and children higher levels of certain PFAS chemicals were associated with weaker responses to vaccines. The Agency for Toxic Substances and Disease Registry, a division of the CDC, recognized this evidence in an announcement it recently posted to its website on the “potential intersection between PFAS exposure and Covid-19.”
With the pre-pandemic knowledge of the effects of individual chemicals and the maps showing that Covid-19 is ravaging polluted areas, the next step for researchers is to address how exactly chemicals make individual people more susceptible to Covid-19. “We now know pollution is associated with increased infections and more hospitalizations,” said Birnbaum. “So it has a role. The question is how much of a role and how do you show that an individual is getting sick is because they have higher levels?”
Philippe Grandjean, a Danish scientist who was the first to show that children with relatively high PFAS levels had immune deficits and were more likely to get respiratory infections, has already begun to try to answer this question. Grandjean is in the process of collecting blood samples of people who were hospitalized with Covid-19 — “just a few drops of the serum from leftover blood samples that hadn’t been used” — analyzing them for PFAS levels, and comparing them with PFAS levels from the blood of people who were infected with the coronavirus but not hospitalized.
“We really need to understand the connection between exposures at the individual level and Covid-19 severity,” Grandjean said. While noting that several environmental contaminants likely increase the risk of the disease, Grandjean expressed particular concern about PFAS compounds because they can remain in the body for years and some of them tend to concentrate in the lungs. Grandjean, who is conducting the research in Denmark, hopes to have results of the study within the year.
Others are using animal experiments to explore how chemical exposure affects the impact of the coronavirus. Paige Lawrence, a professor of environmental medicine at the University of Rochester School of Medicine and Dentistry, plans to infect mice with a mouse-adapted human coronavirus that was built from the 2003 SARS pandemic and study how exposure to PFAS alters the course of the viral infection.
“We need to understand at a cellular level what’s changed” by chemical exposure, she said. “We can’t improve health if we don’t know what we’re trying to fix.” Lawrence’s past research has shown that the environmental contaminants dioxin and PCBs change the immune system by binding to receptor cells — an effect that, in the case of dioxin, lasts for generations.
While the research is underway, many of the people in highly polluted communities worry about the greater risk they may face during the pandemic. “I think about it a lot,” said Hope Grosse, a resident of Warminster, Pennsylvania, who developed stage 4 cancer while drinking water that had been contaminated with PFAS from firefighting foam used at a nearby naval base. “My immune system was definitely impacted.” Grosse, who had 25 lymph nodes removed during her cancer treatment, resumed her work as a realtor last month and wears gloves and a mask when she shows houses. “I’m as careful as I can be, but I still worry,” she said.
Whatever we learn from the research now in the pipeline, some scientists say there is already enough evidence to lay blame for at least a portion of the toll of the virus on chemicals — and their manufacturers.
“Endocrine-disrupting chemicals are clearly involved in driving the comorbidities and are heightening mortality risk from Covid-19,” said Pete Myers, founder and chief scientist of Environmental Health Sciences. “You can’t hide from that truth.” Myers is one of several environmental scientists who have been pushing for more than a decade — with little success — for government to limit the use of these chemicals.
“The American Chemistry Council has impeded our ability to develop meaningful regulations,” said Myers, referring to a powerful chemical industry trade group. “And the result of that is that these comorbidities that have become epidemic over the last three decades. And now more people are dying than would have.”
The American Chemistry Council did not immediately respond to a request for comment for this story.