Understanding the CDC’s new masking guidelines.

How they work. What they get right … and what they don’t.

On Friday, the Centers for Disease Control and Prevention issued new COVID guidelines, declaring it safe for most healthy people across the country to take off their masks. Beyond simple “on” or “off” recommendations, these guidelines offer a new framework for masking.

Before we cut into the guidance itself, it’s worth taking a quick stroll down memory lane. The CDC first reversed its recommendation around masking last May, after the initial demand for vaccinations started to ebb. CDC Director Rochelle Walensky announced new guidance allowing vaccinated people to go without masks in all indoor settings. Hot Vax Summer was on the way!

But it was clear from the jump that the policy guidance was a gamble. I wrote about why in these pages:

On the one hand, [this CDC guidance] could incentivize enough people to finally get their vaccines to get back to life as they once knew it so that all of us can get back to life as we once knew it. On the other, it could backfire—the unvaccinated may free-ride on the policy to forego not just their vaccines, but their masks too. Putting themselves and others at risk in the process, they could perpetuate the pandemic.

At that time, the CDC was, inadvertently, declaring victory over a pandemic whose wiles we were only beginning to fully understand.

As case rates began to quickly tick back up, we came to understand that vaccination may not offer complete protection. That came into full relief after a study was released following a 466-person outbreak at a public gathering in Provincetown, in which more than three in four of those infected had been vaccinated. An analysis of the cycle thresholds — a measure of the viral load and capacity to infect others — among vaccinated people showed that they were similar to unvaccinated people. On that information, Director Walensky announced a reversal of the masking guidelines to recommend universal indoor masking in communities with “substantial or high” rates of transmission. These are the guidelines we’ve been living with ever since — through delta and omicron. 

The CDC’s initial gamble failed. The public had seen the U.S.’ most important public health agency reverse course again. 

Soon after, with the advent of omicron, nearly the entire country was pitched into universal masking territory. Whereas delta was more transmissible, more vaccine evasive, and more severe than previous variants, omicron traded severity for more of the other two features. While maintaining public masking guidelines through the omicron surge was clearly important, omicron posed a unique set of circumstances as it abated: how should the reduction in severity change COVID precautions from here?

This is a loaded question that explodes quickly into a series of other ones. COVID is not gone. But then it will likely never be. So what level of risk are we willing to tolerate? What are the equity implications of any risk at all? What are the risks of another variant that could cause a major outbreak and how do we hedge against them?

States and municipalities began answering these questions quickly, as nearly every single state in the country — red or blue — repealed universal mask mandates. 

And that left the CDC increasingly out of step with prevailing sentiment. 

The CDC was once bitten, twice shy. They had declared victory and failed before. That’s the context in which the CDC introduced its new guidance. Let’s cut in.

How the guidelines work.

Rather than recommend masks simply based on the level of COVID transmission, the guidelines stipulate three metrics around which county-by-county decisions should be made. Along with the community transmission rate, the guidelines consider the COVID hospitalization rate and the proportion of hospital beds occupied by COVID patients. Using an algorithm, counties are given a low, medium, or high risk designation, which is updated weekly. In low-risk settings, public indoor masking is not recommended. In high-risk settings, it is. And in medium-risk settings, individuals are recommended to “speak to your healthcare provider.”

Let’s unpack some of the rationale behind the new guidance. Beyond the risk of infection (COVID case rates) the guidelines consider the severity of cases and the risk to the healthcare system. The severity of symptoms are reflected in the rate of hospitalizations, or the number of new COVID hospitalizations over time. Presumably, if there were a new, more severe variant, the number of hospitalizations would rise, triggering new masking recommendations. The guidelines also aim to protect the healthcare system — which is why the CDC included the proportion of hospital beds in their calculation.

What the guidelines get right.

First and foremost, these new guidelines meet the pandemic where it is. Cases are down substantially across the country and hospitalization and death rates are plummeting as well. States and municipalities have rushed to downscale their masking requirements.