I wonder how many people who agree that this dumb new mask rule shouldn’t be enforced also took the view that “rules are rules” in justifying kicking Sha’Carri Richardson out of the Olympics.

I’m not a fan of cops deciding for themselves which laws should and shouldn’t apply but L.A.’s new indoor mask mandate won’t do much to reduce the spread of Delta whether it’s enforced or not. Risk-averse people (i.e. the vaccinated) were going to mask up anyway in response to the surge in cases while risk-tolerant people (the unvaccinated) are destined to shirk the rule to whatever extent they can get away with. And there’s something to be said for the argument that making vaccinated people wear masks again at a moment when the feds are trying to persuade holdouts to get their shots may backfire by convincing them that vaccination alone won’t do much to protect them.

Is it true, though, as sheriff Alex Villanueva says, that wanting the vaccinated to mask up indoors isn’t supported by science?

Sort of yes, sort of no.

Forcing the vaccinated and those who already contracted COVID-19 to wear masks indoors is not backed by science and contradicts the U.S. Centers for Disease Control and Prevention (CDC) guidelines. The Los Angeles County Department of Public Health (DPH) has authority to enforce the order, but the underfunded/defunded Los Angeles County Sheriff’s Department will not expend our limited resources and instead ask for voluntary compliance. We encourage the DPH to work collaboratively with the Board of Supervisors and law enforcement to establish mandates that are both achievable and supported by science.

Sheriff Alex Villanueva

He’s totally right that current CDC guidance says you don’t need to wear a mask indoors if you’ve been immunized. But a few weeks ago, after L.A. County started “strongly recommending” masks indoors for all residents, CDC chief Rochelle Walensky said she’d defer to local authorities on what precautions to take as cases began rising again. And she made an important point:

“Those masking policies are not to protect the vaccinated, they’re to protect the unvaccinated,” she says. “If you are vaccinated, you are safe from the variants that are circulating here in the United States.”

Asking the vaccinated to wear a mask during a Delta surge isn’t about trying to prevent them from getting COVID, as they have little to fear. It’s about trying to prevent them from unknowingly infecting unvaccinated people. That’s the central mystery right now: How many fully vaccinated people are walking around, possibly asymptomatic, and transmitting the super-contagious Delta strain to others? A few months ago the CDC was confident that the vaccinated weren’t passing along the virus to others. How confident are they that that’s still true with Delta?

Scott Gottlieb told CNBC yesterday that he suspects there’s a huge number of vaccinated people infected with Delta right now and they either don’t know it because they’re asymptomatic or their symptoms are so mild that they think they have some other virus:

“I think we’re vastly underestimating the level of Delta spread right now because I think people who are vaccinated, who might develop some mild symptoms and might develop a breakthrough case, by and large are not going out and getting tested,” Gottlieb said in an interview on CNBC’s Squawk Box. “If you’ve been vaccinated and you develop a mild cold right now, you don’t think you have Covid.”

I’ve written about that before. If you’re vaccinated, you have little incentive to get tested at this point. Even if you develop the telltale symptoms of COVID and think you’ve been infected, you’ll reassure yourself that you’re protected and that it’ll pass in a few days if you ride it out. Follow the last link and watch the clip of Gottlieb and you’ll find him extending that logic to the unvaccinated too: If you’re young and healthy and develop the familiar symptoms, you’ll shrug in the expectation that you’ll be over it in no time and will also ride it out. Neither group has any reason to bother with a test unless their symptoms worsen.

Which means the data is probably missing an enormous number of infections across the population. The million-dollar question is whether vaccinated people who are infected but experiencing few or no symptoms are capable of passing the new variant to others. A study of Delta published this week showed that infected unvaccinated people shed a thousand times as much virus with the Delta strain as they did with the original SARS-CoV-2. How much are vaccinated people shedding by comparison?

Enough to threaten the unvaccinated people around them? Because if so, wanting the vaccinated to mask up does have a solid scientific basis. And as reluctant as the CDC is to tighten their guidance again after relaxing it a few months ago, they may have no choice soon.

Other urban areas probably aren’t going to wait around for them, though. A New York City Councilman who chairs its health committee says it’s time:

The rule of thumb should be: in indoor settings where there's no screening for vax/test status, everyone should wear a mask.

This must include vax'd because there's a very small chance they can still receive/transmit, & because we need mask solidarity. Otherwise it doesn't work.

— Mark D. Levine (@MarkLevineNYC) July 17, 2021

Health officials in the part of Nevada that includes Las Vegas are also now recommending masking indoors to try to slow down the rising statewide outbreak, which just produced the biggest single-day surge in cases since February. If people comply, it might help a little.

But ultimately there’s only one solution:

A new ABC analysis has found that over the past week, states that have fully vaccinated less than 50% of their total population have reported a weekly average coronavirus case rate that is three times higher than in states that have fully vaccinated more than half of their residents.

States that have fully vaccinated more than half of their residents reported an average of 15.1 new COVID-19 cases per 100,000 people over the last week, compared to an average of 45.1 cases per 100,000 people in states that have vaccinated less than half of their residents.

The 14 states with the highest case rates all have fully vaccinated less than half their total population, and 10 out of the 11 states with the lowest case rates have fully vaccinated more than half of their total population, with the exception being South Dakota.

South Dakota’s the exception because its outbreak last year was so horrendous that they may have reached herd immunity from the sheer scale of contagion that swept through the state.

I’ll leave you with Gottlieb’s prediction that this is *probably* the last major wave the U.S. will endure for the simple reason that so many Americans will get infected by Delta by the time it’s done that there won’t be many non-immune people left to fuel a future wave — essentially the South Dakota experience on a national scale.

"The canary in the coal mine, unfortunately, is going to be the nursing homes," says @ScottGottliebMD on when we'll learn #covid immunity wears off. "The infection is eventually going to get into these settings … it's going to shoot around a facility like that." pic.twitter.com/lobuQ5dWjr

— Squawk Box (@SquawkCNBC) July 16, 2021