A new study from Harvard University researchers concluded that approximately 20% of COVID-19 cases in California and Washington state were linked to wildfires that took place in the area.

“Clearly, we see that, overall, this is a very dangerous combination,” said Francesca Dominici, a biostatistics professor at Harvard and co-author of the study. “It’s a really scary thing as we continue to face these wildfires all around the world.”

Last year, while the pandemic was raging both nationally and across the globe, wildfires were doing much of the same on the west coast of the United States, particularly in California, Oregon, and Washington.

In California in particular, the state went through five of the six largest wildfires in their history. Currently, the Dixie Fire that has overtaken the state is the second largest fire in state history, according to The Washington Post.

Similar studies regarding air quality and COVID-19 have proven that significant air pollution can cause worsened coronavirus symptoms.

The Centers for Disease Control and Prevention has already stated that wildfire smoke can make individuals “more prone to lung infections, including SARS-CoV-2, the virus that causes COVID-19.”

In their study, Harvard researchers utilized information on COVID-19 cases in deaths in counties affected negatively by the wildfires. Along with using satellite data to track quantities of particulate matter, researchers were able to conclude that there is “strong evidence” linking increases in poor air quality to COVID-19 cases and deaths.

“We found that, in some of the counties, the percentage of the total number of COVID-19 cases and deaths attributable to the high levels of PM2.5 was substantial,” the study read.

For those living in these troublesome spots, Dominici and her team suggest that they get vaccinated.

“Especially in these counties, I think that absolutely everybody should get vaccinated ASAP, because this study points [out] that these counties can be more affected, both in terms of cases and deaths,” she said. “I understand it’s not feasible for everyone, but to the degree they can: Move and be away from this exposure to wildfires at this time we have this delta variant coming in.”