In-Depth: How safe are crowds in San Diego after California reopens?

Experts warn of COVID spread in large crowds
Virus Outbreak masks crowd
Posted at 11:07 AM, Apr 27, 2021
and last updated 2021-04-27 11:07:57-04

SAN DIEGO (KGTV) - This week, San Diego County moved another step closer to a full reopening from COVID-19 related business shutdowns. The county entered the orange tier in the state's Blueprint For a Safer Economy, allowing businesses to expand capacity.

Meanwhile, Gov. Gavin Newsom said he expects California businesses to reopen fully by June 15 if vaccinations are available and hospitalization numbers remain stable.

That's good news for business owners, who hope to welcome back customers and make up some of the money they lost last year.

But coronavirus experts say it doesn't mean the risk of spreading the disease is over.

"Certainly, some spaces will be much more safe than others," says MIT Professor Martin Bazant.

Bazant created an online tool to determine how much risk any given environment will have. It uses factors like room size, crowd size, and length of exposure to calculate how safe you may be.

He says the best way to think about COVID-19 exposure going forward is to compare it to secondhand smoke.

"The risk of secondhand smoke becomes reduced when the space is large," says Bazant. "Having a high ceiling in a room is good. Having open windows is good. Ventilation is very important."

Bazant says the comparison is critical when you think of COVID-19 as an airborne disease.

According to the latest CDC science brief, COVID-19 is still a "respiratory threat," not an airborne disease. But it's a nuanced distinction based on the size of the viral particle and how long it can stay in the air.

Even without labeling it an "airborne" threat, the CDC still says "Ventilation and avoidance of crowded indoor spaces" are important things to consider.

Local doctors feel airborne spread of the disease should be the primary concern from now on.

"There have been studies that show that it can stay in the air for upwards of five to ten minutes, or even longer," says Sharp Rees-Stealy Dr. Jyotu Sandhu. "So, you might not know you're walking through an area that's infected when you're not seeing anybody around."

Sandhu says people who choose to go into crowded places can do three things to stay safe: wear a mask, get vaccinated, and maintain social distancing. He says doing that will help in almost any situation, but it's essential at events where people will be singing, shouting, or laughing.

"Right now, we're playing it safe," says Dr. Sandhu. "We're telling people to assume that it can spread through the air for quite a bit of time."

Dr. Sandhu says you can also do things like sit near a door or window or limit your time inside a venue to lower the risk.