New CDC (mask) guidance: My two cents

This afternoon the CDC provided on- and off-ramps for public health mitigation measures (like masks) going forward. The CDC made it clear that the sole purpose of the new framework is to prevent severe disease and, thus, not overwhelm hospital systems at the local level.

What’s the guidance?

Briefly, the CDC packaged three metrics for every county in the U.S.:

1. New COVID19 hospital admissions over the previous week;

2. Percentage of hospital beds occupied by COVID patients; and,

3. New cases per 100,000 people over the previous week.

They then corresponded these metrics to categories: low (green), medium (yellow), and high (orange).

(CDC)

The CDC then mapped these metrics to behaviors, like masking. So, for example, if a county is in the “orange”, everyone needs to mask indoors. If a county is in the “yellow”, then only high-risk individuals should mask.

The CDC provided a live, map that displays the color of every county. It will be updated weekly. Today, about 70% of counties are in yellow or green. In other words, about 70% of counties don’t need to mask indoors.

(CDC)

My two cents

As many of you know, I’ve been one of CDC’s biggest critics throughout this pandemic. But… I’m pleasantly surprised with this framework for a few reasons:

Praises

1. Cases included. The CDC ended up integrating case metrics into their framework and this was 100% the correct call. Before today, rumors suggested that the CDC was only going to use hospitalizations to map behaviors. But this is inherently flawed because once hospitalizations increase, transmission in the community has already been high for about 3-4 weeks. So, I’m glad they decided not to do this.

2. Hospitalization definition. The CDC is counting hospitalizations “with COVID” and “for COVID19” in their hospital metrics. This is also, absolutely, the right call. First, some jurisdictions just don’t have the capacity to differentiate the two. But, second, because Omicron showed us that there’s actually a third category that isn’t clearly differentiated: “COVID19 exacerbating medical conditions.” For example, if a child has diabetes, COVID19 infection significantly complicates the disease and the child is hospitalized “with COVID” not “for COVID19”. But, this is very different than a child with a broken bone that happens to test positive. So, I’m happy that the CDC is counting everything because everything does impact supply, staff, and hospital capacity.

3. Layered approach. The CDC did not just map these metrics to masks. They also mapped the metrics to our other tools, like rapid testing (when and how), ventilation of spaces, vaccines, treatment, etc. I was VERY happy to see this. Yes, masks work. But so do all the other tools we have significantly underutilized throughout the pandemic.

4. Dial up and dial down. Given my proposed framework a few weeks ago, you won’t be surprised to hear how happy I am the CDC provided guidance on how to “ride the waves”. The end of a surge is not the end of a pandemic. We need to be prepared and ready for the next. It may never come. But in the high likelihood that another wave does come, we need clear guidance.

5. Vaccination rate. This is minor, but I’m glad they didn’t include community-level vaccination rates in their metrics. Vaccinations are already folded into population-level hospitalizations, so they are already accounted for to some degree. Also, I have yet to see any scientific evidence that vaccines reduce Omicron transmission. They did for Delta, but I would want to see this data first before assuming so for Omicron.

6. Transportation. This guidance is NOT for public transportation, like planes. All of the masking requirements still pertain (at least until mid-March). The CDC said they’re evaluating the situation and will comment in the coming weeks.

Critiques

I wouldn’t be a scientist without critiques. I think these critiques are pretty big, too:

• Case level definition: It’s not clear to me how they arrived at their new case metric: 200 cases per 100K in the past week. (Before today masks were needed at 50 cases per 100K in the past week). No scientific justification was provided. And I’m shocked the CDC is comfortable with this high level of transmission given long COVID19 implications, given that not everyone has access to the vaccine, and given high excess death to high risk individuals (like we’re seeing in Denmark with high levels of transmission. Vaccines are great but not perfect).

  To demonstrate, this morning the CDC’s old guidance said that 3,074 counties should wear a mask indoors. This afternoon their new guidance says only 1,200 counties need to mask. This is a big difference. And, honestly, I’m a bit uncomfortable with this high level of transmission in the community.

• I also didn’t appreciate a few places where the guidance said, “If you are immunocompromised or high risk for severe disease… talk to your healthcare provider”. So, this framework isn’t public health guidance. This is individual-level guidance and only for certain individuals. The CDC is THE public health leader and really needs to lead that way. As a boosted individual, I know my individual risk is very, very low. But I also understand that other people’s risks are high. I would like guidance on how to adequately contribute to society for these folks’ benefit too (not just until they show up at the hospital).

Because of these two critiques, I will still be wearing my mask at “yellow”. Once we reach green, which should be soon, I’ll celebrate taking it off… at least until we reach yellow again.

Have a great weekend!

Katelyn

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“Your Local Epidemiologist (YLE)” is written by Dr. Katelyn Jetelina, MPH PhD—an epidemiologist, biostatistician, professor, researcher, wife, and mom of two little girls. During the day she has a research lab and teaches graduate-level courses, but at night she writes this newsletter. Her main goal is to “translate” the ever-evolving public health science so that people will be well equipped to make evidence-based decisions. This newsletter is free thanks to the generous support of fellow YLE community members. To support the effort, please subscribe here: