COVID-19 and the Environment: Is There a Relationship?

COVID-19 and its shelter-in-place orders have brought a welcome relief in many places from air pollution and the worsening environment. But did the longer trends of climate change, habitat destruction, and urban pollution play a role in COVID-19’s appearance and spread?

That would be hard to prove, but there are some theories linking them. “In the past century, we have escalated our demands upon nature, such that today, we are losing species at a rate unknown since the dinosaurs, along with half of life on earth, went extinct 65 million years ago,” Aaron Bernstein, MD, director of the Center for Climate, Health, and the Global Environment at Harvard, said in a conversation posted on the university’s website. “This rapid dismantling of life on earth owes primarily to habitat loss, which occurs mostly from growing crops and raising livestock for people. With fewer places to live and fewer food sources to feed on, animals find food and shelter where people are, and that can lead to disease spread.”

Virus Origins Unclear

The way that the virus got started in the first place isn’t yet clear, but one theory involves another animal-human connection: that the virus started in bats and then got into humans. Some coronaviruses clearly have bats as their reservoir, including the ones that cause SARS and MERS, Bernstein said in a phone interview. However, unlike the specific SARS and MERS coronaviruses, which were actually found in bats, “there’s not direct evidence yet” that bats carry the SARS-CoV-2 coronavirus that causes COVID-19, he added.

Another popular theory is that, just as SARS went from bats through another animal — the civet — and then to people, COVID-19 went from bats to another animal, possibly the pangolin, and then into people; this might have occurred via a Chinese “wet market” in Wuhan that sells exotic animals, including pangolins. However, “the pangolin theory is pretty murky,” said Bernstein. “We don’t know if the virus went from a bat to a person or through another animal, and that may never be known.”

And, of course, suspicions have arisen that the virus escaped from a research lab in Wuhan, now backed by U.S. Secretary of State Mike Pompeo and others, though without much evidence. U.S. intelligence officials have determined the virus was not manmade, but a lab in Wuhan does conduct research on potential zoonotic pathogens, and the “wet market” origin theory has its doubters.

Local Air Pollution

No matter how it happened, now that COVID-19 is here, researchers are seeing that its effects on people may be determined in part by the environment in which they live. “Those who live in more polluted environments, areas where there’s more particulates in the air and more ozone smog in the air, are more likely to have problems with their underlying asthma or chronic lung conditions,” Mona Sarfaty, MD, MPH, founding director of the Medical Society Consortium on Climate and Health at George Mason University in Fairfax, Virginia, said in a phone interview. And “it’s been all over the news that people who have become infected with coronavirus are more likely to crash if they have an underlying compromise with their lungs because of an underlying lung condition.”

Often, the poor air quality occurs in densely populated poor neighborhoods, Stephanie Lovinsky-Desir, MD, assistant professor of pediatrics at Columbia University in New York City, said in a phone call. “The air pollution in New York City — it’s sort of, in certain communities and neighborhoods, a little bit higher,” she said. “If you think about diesel exhaust from garbage trucks and traffic, and waste transfer vehicles; those waste transfer stations tend to be in the most poor communities, so there’s more pockets where pollution exposure is pretty high.” That lends itself to the idea of a “two-hit model” for COVID-19 in which “there is a confluence of things that influence the risk, and maybe pollution is a piece of the puzzle,” along with a denser population, she added.

To try to tease out the various factors, Lovinsky-Desir and colleagues are collecting data across New York City. “We’re still in the early stages of collaborating with colleagues across the city at different institutions, and we really want to get a sense of who are the people who’ve been hospitalized with COVID-19 — indicating a severe infection — to see where did those people live?” she explained. “We can tie back to their zip codes of residence and get a sense of their chronic exposure to air pollution as a factor for severe infection with COVID-19.”

Role for Clinicians

Clinicians have a role to play in reducing the risks posed by climate change in relationship to COVID-19 as well as other diseases, Sarfaty said. “We’d like to have the medical community become vocal about how important it is to adjust our way of life so that we produce less air pollution, and this will not only improve our health, it will create a lot of jobs too.”

Bernstein asserted that clinicians need to speak up about policies that are harming human health and the environment. COVID-19 “is a sentinel event for healthcare; we cannot deal with this kind of problem,” he said. “I hope part of the response of healthcare is not simply asking for more taxpayer money, but advocating for policies that protect us from this kind of shock … especially given the health status of the U.S. population” and its underlying chronic conditions that make it more vulnerable. “It’s not the responsibility of healthcare to figure out how to solve the upstream problems, but we have to be talking to policymakers.”

Novel pathogens come predominantly from wildlife, “and we in the U.S. are the largest importers of wildlife in the world, and we’re more responsible for people going into the wilderness and harvesting animals mostly for people who have pets, and fueling economics that lead to massive amounts of deforestation, which is another major driver of this problem,” he said. “It does not have to be a ‘throw-out-everything-at-once’ proposition; some species are more at risk of being reservoirs of disease than others. We have to look really hard at this problem.”

Last Updated May 05, 2020