During the pandemic, we’ve learned that outdoor interactions are less likely to spread COVID-19 than indoor ones. But with the latest coronavirus variants – like BA.5 – being so much more transmissible, is it time to wear a mask outside more often?
The emergence of BA.5 and other highly contagious Omicron subvariants is definitely of concern, experts said. And while outdoor gatherings are still considered safer, there are some instances when it makes sense to dress up — even when you’re outside.
Outdoor interactions are still generally much safer than indoor ones
More than two years into the COVID-19 pandemic, we know a lot more about how the coronavirus is spreading than we did in March 2020, experts told TODAY.
At this point, SARS-CoV-2 appears to spread primarily when a person infected with COVID-19 expels respiratory droplets containing parts of the virus, said Linsey Marr, Ph.D., an expert in aerosol transmission of viruses Professor of Civil and Environmental Engineering at Virginia Tech.
In certain environments, these droplets can become aerosolized, said Dr. Scott Roberts, associate professor and associate medical director for infection prevention at Yale School of Medicine, TODAY.
When that happens, the aerosolized particles “behave like cigarette smoke,” Marr explained. “They’re most concentrated near the person who released them, and they can also float for long periods and spread throughout space.”
Tiny droplet nuclei, formed when larger droplets hit the ground and evaporate, could also play a role, Roberts said. These “can travel much farther and stay airborne much longer than the actual droplet,” he said.
Indoor environments without much airflow trap these particles inside. “The virus can become airborne and accumulate over time,” Marr explained.
Inside, you can create a safer environment by circulating air through a space, Neysa Ernst, nurse manager at the Johns Hopkins Biocontainment Unit, told TODAY. “But of course that happens outdoors,” she said.
When you’re outdoors, the particles aren’t trapped by walls or ceilings, Marr said. “They kind of disperse quickly and get more diluted in the outside air” and therefore make others less sick. That’s why things like outdoor concerts or protests in general weren’t super spreader events, she said.
But being outdoors is no guarantee of safety
The virus “spreads much less easily outside than inside. And by moving events outdoors, you drastically reduce the risk of transmission,” Roberts said. But even outdoors, the risk “is probably not zero,” he said.
There are certainly situations where COVID-19 can spread, even when you’re outside, Roberts said, like a full shoulder-to-shoulder concert. “If I have one foot next to someone and they sneeze in my face,” he said, “it’s pretty hard to avoid a large (amount) of COVID.”
So, now that even more transmissible variants like BA.5 are rife, are you more likely to contract COVID-19 outdoors?
Unfortunately, there isn’t much data on whether Omicron and its subvarieties are more likely to spread outdoors than previous cultivars, Roberts said. “But anecdotally, I’ve heard more reports from people who have tested positive and say they could only have gotten it outdoors,” he said.
“Overall, the risk has probably gone up a bit outdoors because these new variants are more easily transferrable,” Marr said. “But that’s been since Delta,” she added.
And so far, BA.5 appears to be more easily transmissible because it can more easily bypass our existing immune protections, not because it causes people to release more virus particles when they cough, for example, Marr said.
So if you’re exposed to the virus, whether you’re indoors or outdoors, you can get COVID-19 more easily now than in previous waves. But being outdoors is still generally safer than being indoors, where you could become trapped with aerosolized particles.
How to protect yourself:
“If you have any kind of gathering, it’s much better to do it outside,” Ernst said.
But not all outdoor events are created equal, Roberts added. A picnic in a park or your backyard with a few friends is likely to pose less of a risk than, say, a crowded sporting event full of screaming fans.
If you’re someone at higher risk for severe COVID-19 symptoms, or you just want to take an extra precaution, wearing a mask is one of the easiest and most effective ways to protect yourself outside, the experts said.
“Have a good mask,” Ernst advised, especially if “you’re going to be around people you’re not related to and you can’t be sure of their vaccination status.”
Although the vaccines are not as effective in preventing BA.5 infections, they still do a good job of protecting against the serious effects of COVID-19. Increased transmissibility “is a cause for concern,” Ernst said, “but it’s a more important reason to get vaccinated and boosted.”