Public Health Update: Indoor Masking “Strongly Recommended” Again

As LA County’s COVID-19 weekly case rate moved back up to 100 cases per 100,000 residents this week, the LA County Department of Public Health announced that wearing masks in indoor public spaces is now “strongly recommended” for all individuals.

The announcement was made by LA County Health Officer Dr. Muntu Davis at the DPH’s weekly public health update yesterday.  Since September, masks have been a matter of personal choice in most public spaces (though still recommended on public transportation and required in health care settings). But increasing case counts in October and November led LA County Public Health Director Barbara Ferrer to note last week that if our case rate, which was then at 86 cases per 100,000 residents, rose to 100, indoor masking recommendations would return. And we hit that point yesterday.

This means that while masks are still not required, they are now strongly recommended in public indoor spaces, on public transit (including buses, trains, ride shares, taxis and medical transport vehicles), at correctional and detention facilities, and in homeless and emergency shelters.

And, of course, masking is still required, as it has been all along, for people who have been exposed to COVID-19 within the past 10 days, in healthcare and congregate living facilities, and anywhere else a business or other organization chooses to require it.

Despite the increasing case numbers, however, Davis also reported that the current case rate is still well within the “low” community tier, as defined by the CDC, though all three factors that influence that level have been rising recently.  The “low” designation, however, means that our hospitals and other community health resources are not currently stressed by current levels of the virus.  So masks won’t become mandatory again unless and until LA County moves up to the “High” community level (at which health care resources are being stressed), and stays there for at least two weeks.

As for which strain(s) of the virus are causing the current upticks, Davis reported that newer Omicron BA.5 subvariants BQ.1 and BQ.1.1 are both increasing rapidly, while BA.5, which dominated the local COVID picture for most of this year, has been receding quickly since October 1.  And yet another new variant, BN.1 (a sub-variant of BA2.75.5), was added to the list of locally-tracked strains this week.

As has has been the case for the last few weeks, flu and Respiratory Syncytial Virus (RSV) are also still very much a part of our current public health picture, Davis said, with flu, in particular, off to an early and particularly fast start for the season.  And that means, Davis said, people who have not yet received their annual flu vaccines should do so as soon as possible.

Also, since masking can also help prevent the spread of flu and RSV, in addition to COVID-19, Davis said it is a simple and effective way for people to protect themselves and others from all of the major respiratory viruses currently circulating.

But Davis also said yesterday that the new mask recommendations shouldn’t derail people’s plans for the upcoming Thanksgiving holiday.  People can still celebrate safely by wearing masks indoors, making sure they’re up to date on their COVID-19 vaccines (something that’s true for only 14% percent of LA County residents so far), testing before you go to a large gathering (or asking guests to test before they come to your gathering), staying home if you’re sick, and staying outside or increasing indoor ventilation as much as possible.

Davis also cited results from a recent Harvard University study that showed the overall COVID-19 case rate for Massachusetts school districts was almost twice as high as that for districts that required masking for all students.  And during periods of higher COVID-19 transmission, Davis said, the gaps between districts with mask rules and all districts was even greater. “This indicates universal masking policies were most effective during periods of high transmission,” Davis said.  So “it’s reasonable to assume that the effectiveness of masking is relevant in non-school settings as well.”

So masking and other simple protections become even more important as the holidays approach and people attend more large gatherings, creating ever more opportunities for exposure.  For example, Davis reported that when the case rate is 50 per 100,000 residents, there’s a 25-35% chance that, in a gathering of 200 people, you’d be exposed to 1 or more people who are infected with COVID-19.  But when the case rate is 100 per 100,000 residents, as it is this week, those odds rise to 45-60% in a gathering of the same size.  And they rise to a 60-75% chance of contact with an infected person in a similar-size gathering when the case rate rises to 150 per 100,000 residents.  “So there’s a high probability that you will be exposed to someone with COVID, and the probability increases as the case rate increases,” Davis said.  “Wearing a mask indoors can reduce the risk that COVID spread to you, and subsequently to those around you.”

Monkeypox

Finally, in other public health news, LA County Chief Medical Officer Rita Singhal reported at yesterday’s briefing that although the county has now recorded its second death from monkeypox, cases of  that disease continue their “substantial decline,” with an average now of only three new cases reported per day (compared to 20 a day just two months ago).  And, even better, Singhal said, LA County experienced its first day without a new case (since the outbreak began in June) on Tuesday of this week, and there’s been only 1 new case reported since then.