CINCINNATI, Ohio — The CDC is planning to weigh in soon on whether we should update our masks, especially as the omicron variant surges across the country.
But it’s creating some confusion over which masks are most effective.
Early in the pandemic, before omicron and delta variant surges, the American Conference of Governmental Industrial Hygienists (ACGIH) in Cincinnati, known for curating guidelines for employee workplace conditions, compiled an estimated guidance for mask protection against COVID.
“You don't know if you're infected or if you're going to be infected. So, the idea was to think about if you're not infected, what's the impact of someone or people around you wearing something on their face,” said Dr. Lisa Brousseau Chair of the ACGIH Pandemic Task Force.
So based on published research, the group made a chart showing which masks work best to hold off the spread of COVID-19. For example, with two people wearing cloth masks, it can take about a half-hour to spread the virus. For two people wearing surgical masks, it can take about an hour. Lastly, for two people wearing N95 masks, it can take 25 hours.
“My idea was let's just take the contact tracing time, the 15 minutes that CDC proposed and build on top of that. So, that at least that assumes that it takes you on average about 15 minutes of time in close proximity to somebody who's infected in a shared space to get an infectious dose. Of course, that isn't based on any science. Let me be really clear, so that's just a good guess on the part of CDC,” Dr. Brousseau explained.
Moreover, just as the virus changed, so has research.
A new study from the UK now estimates the virus loses most of its ability to infect within the first 5 minutes of leaving someone's body, while other variables like a person's environment should be considered.
“You shouldn't be saying, well if you only go in and spend 15 minutes with somebody, you're going to be fine, you know, because as I said, there might be lots of sources in the room. The concentration might be very high, the ventilation might be really bad, people might be singing or coughing or talking. So, there might be much more particles than you expect,” Brousseau said.
Brousseau believes the cloth or disposable masks most Americans are wearing today are not as effective as originally estimated and she doesn’t “agree with the CDC when they say, well, any mask is better than no mask.”
As the CDC considers recommending Americans only wear KN95 or N95 masks, Brousseau warns they're only effective if fitted properly; snugged on your face with no gaps.
“If an employer is giving a respirator to an employee to protect them from a hazard at work, they're required to fit test, but if the public starts wearing respirators, clearly there's no easy way to get fit tested,” said Brousseau. “I think we will end up with better designs that are comfortable and that people will accept to wear.”