How wildfire smoke driving people inside lately could affect the spread of the new coronavirus

©The Seattle Times

Mike Siegel/Seattle Times/TNS

SEATTLE — The outdoors has been a lifeline for many in Seattle during the COVID-19-induced lockdown. It gave us somewhere to go when gyms and restaurants were closed, and gathering (in small numbers, distantly, with masks) outdoors is much safer, coronavirus-wise, than doing so indoors.

But that outlet has been choked off over the past week and a half by wildfire smoke.

The acrid air smothering the Puget Sound region was rated “unhealthy,” “very unhealthy,” at times even “hazardous” by the state Department of Ecology. The advice for avoiding it: stay indoors.

Assuming people followed that advice, what effect might it have had on the spread of the coronavirus that causes COVID-19?

Here are some questions and answers.

— If people are spending more time indoors to avoid wildfire smoke, how could that affect the spread of the coronavirus?

It depends on how people spent time indoors.

If people all hunkered down with the same people they’ve been with since Gov. Jay Inslee’s stay-home order began in March, that could help slow the virus’s spread.

“Staying inside probably decreases their risk because they’re not going out and doing things that put them at risk to be exposed to COVID that they’re then bringing home to their airspace, in their houses, and exposing their families,” said Dr. Chloe Bryson-Cahn, associate medical director of Harborview Medical Center’s infection prevention program.

On the other hand, if avoiding the outdoors meant more people opted to sit inside a restaurant or bar, or have people over inside their homes, that’s another story.

It’s important to keep your circle of people the same and not introduce new people by way of an indoor gathering because of the poor air quality, Dr. Jeff Duchin, public health officer for Public Health – Seattle & King County, wrote in an email.

“We know that the risk of transmission of COVID-19 increases indoors, especially with prolonged contact in confined spaces, with poor ventilation and if people are not wearing masks,” Duchin said.

We’ll be able to see the outcomes from this period of time as new infections are detected in the coming weeks.

But keep in mind, any uptick could potentially be attributed to multiple factors. For example, Bryson-Cahn is nervous that Labor Day weekend could play a role.

“We have had several holidays in the last couple of months, and all of them have involved increased rates of infection in the subsequent weeks, so I think we can anticipate this Labor Day was a similar event,” she said.

— How does COVID-19 compare to the flu? Which is more widespread? Which is more deadly?

COVID-19 and influenza are both caused by viruses, and both cause respiratory infections that can be transmitted by an infected person’s respiratory droplets.

Since SARS-CoV-2 — the new coronavirus’s official name — was discovered in December 2019, it has sickened about 29 million people around the globe, including about 6.5 million in the United States as of Tuesday.

According to the World Health Organization (WHO), 1 billion people get the flu every year. During this past flu season (Oct. 1, 2019, to April 4 of this year), the Centers for Disease Control and Prevention estimates that somewhere between 39 million and 56 million people in the U.S. caught the flu. This is an imprecise number because the flu is not a reportable disease in many parts of the county.

Because SARS-CoV-2 is new, scientists are still learning about the virus and disease it causes. Early numbers show that COVID-19 is more deadly than the flu. More than 931,000 people have died worldwide from COVID-19 since January, which means a mortality rate of about 3%. According to the WHO, between 290,000 and 650,000 people die from the flu every year, making its mortality rate about 0.1%.

As we head into this next flu season, when two contagious respiratory illnesses will be circulating at the same time, public health officials are urging people to get a flu shot — especially because there isn’t yet a vaccine for COVID-19, although several potential vaccines are being developed.

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©2020 The Seattle Times