When Should You Wear a Mask? The CDC Botched Its Answer

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The CDC announcement that vaccinated people can now go unmasked outdoors was bizarre and confusing. Walking and jogging unmasked were already low-risk activities — and something a lot of people, vaccinated or not, have been doing anyway. Like other public health recommendations and rules, it was issued without a clear rationale or reference to new data.

Some experts took to Twitter to suggest the new guidelines were a form of social engineering — to encourage people to get the vaccine by offering them a reward. 

The government isn’t going to gain public trust by issuing new rules when those changes aren’t backed by new evidence — and therefore feel arbitrary. The recommendations are so confusing that even Anthony Fauci failed to explain them coherently when questioned on the Today Show, even contradicting a chart he showed.

What people need instead is for the CDC to be a trusted source of factual, science-based information about what’s reasonably safe to do, what isn’t, and what level of protection people can expect from the vaccines. 

It’s one thing for politicians to impose rules that are easy for them, and make it look like they care. Most of them aren’t scientists. But we should expect better from scientific authorities.

The CDC did better earlier this year when it announced new guidelines suggesting it was reasonably safe for vaccinated people to socialize indoors without masks, and safe for vaccinated grandparents to visit unvaccinated grandchildren. That was much-needed advice — and it contrasted clearly with what’s advisable for non-vaccinated people.

While the CDC could have done a better job of explaining it, there really is new evidence that vaccines drastically cut back on the odds of dying or being hospitalized for the virus, and they also cut the odds you’ll get a mild or silent case and transmit it. 

The science behind outdoor mask wearing, on the other hand, doesn’t appear to be new. It’s been well understood for roughly a year that outdoor transmission is exceedingly rare. And yet, some experts have been recommending masks outside for different reasons.

One infectious disease expert told me that although the odds a random cyclist or jogger might transmit Covid-19 as they pass me are astronomically low, “normalizing” mask wearing outdoors might make people more likely to mask up in the grocery store. But that’s not science — that’s second-guessing people’s behavior. 

Others just say they think it can’t hurt to ask people and even kids to wear a mask at all times even if it’s overkill. But perhaps there is harm in magnifying the wrong risks.  People have clearly been taking real risks — otherwise the U.S. wouldn’t have had such a massive fall wave. That didn’t come about because people walked unmasked on the beach. 

While there are people on social media vowing to continue to double-mask for months after getting their shots, there are many more members of the public eager to get back to normal life and willing to live with one-in-a-million risks. 

The science of disease transmission and mask wearing is imperfect, but evidence existed months ago that being outdoors without a mask, barring close contact, is pretty safe, and that being in a stuffy room full of people in masks of unknown quality is less so. A new study published in the Proceedings of the National Academy of Sciences backs this up. The risk is primarily indoors, and depends on duration of exposure — how long you’re in the building, as well as how many other people are in there with you. 

The CDC and other health officials should prioritize clear, science-backed communication, and leave the social engineering out of it.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Faye Flam is a Bloomberg Opinion columnist and host of the podcast "Follow the Science." She has written for the Economist, the New York Times, the Washington Post, Psychology Today, Science and other publications.

©2021 Bloomberg L.P.

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