CDC Greatly Exaggerates Risk of Outdoor COVID-19 Transmission

The agency's disease advice is seen as increasingly irrelevant by more Americans.


The Centers for Disease Control and Prevention (CDC) has been largely missing in action when it comes to effectively responding to the COVID-19 pandemic. The agency's chaotic responses during the Trump administration have now given way to absurdly cautious approaches under the Biden administration.

Case in point: On April 27, CDC Director Rochelle Walensky grudgingly acknowledged that fully vaccinated people could gather outdoors and conduct outdoor activities without wearing a mask. She cited increasing data that a person is much more likely to get infected with COVID-19 through close extended contacts indoors. Walensky added, "Less than 10 percent of documented transmission in many studies has occurred outdoors. We also know there's almost a 20-fold increased risk of transmission in the indoor setting rather than the outdoor setting."

As Walensky testified today before the Senate Committee on Health, Education, Labor, and Pensions, CDC officials based their highly cautious threshold estimate of an outdoor infection risk of 10 percent on a February meta-analysis in The Journal of Infectious Diseases. 

As David Leonhardt over at The New York Times makes clear today, Walensky and her agency are wildly overstating the risks of getting infected outdoors. As he explains:

That [10 percent] benchmark "seems to be a huge exaggeration," as Dr. Muge Cevik, a virologist at the University of St. Andrews, said. In truth, the share of transmission that has occurred outdoors seems to be below 1 percent and may be below 0.1 percent, multiple epidemiologists told me. The rare outdoor transmission that has happened almost all seems to have involved crowded places or close conversation.

Saying that less than 10 percent of Covid transmission occurs outdoors is akin to saying that sharks attack fewer than 20,000 swimmers a year. (The actual worldwide number is around 150.) It's both true and deceiving.…

These recommendations would be more grounded in science if anywhere close to 10 percent of Covid transmission were occurring outdoors. But it is not. There is not a single documented Covid infection anywhere in the world from casual outdoor interactions, such as walking past someone on a street or eating at a nearby table.

Keep in mind that the data suggesting that the risk of acquiring COVID-19 through outdoor infection is around 0.1 percent (1 in 1,000) were gathered before vaccines became widely available.

So what do the data say about how protective the COVID-19 vaccines are, irrespective of indoor or outdoor exposures? Even the CDC reports that as of April 26, among the 95 million fully vaccinated Americans only 9,245 had experienced breakthrough COVID-19 infections. Therefore, the risk that a fully vaccinated person wandering about in the wild would be diagnosed with COVID-19 after vaccination is 0.001 percent (basically, 1 in 100,000). Admittedly, some of the reduced risk may stem from continued mask wearing on the part of fully vaccinated people, but even so, it is clear that vaccination confers a huge amount of protection against the virus.

As Leonhardt observes, "The scientific evidence points to a conclusion that is much simpler than the C.D.C.'s message: Masks make a huge difference indoors and rarely matter outdoors."

Over at Stat news, Leana Wen, a George Washington University health policy professor, declared, "If [the CDC's] advice is too disconnected from reality, and if they are too slow, then they make themselves irrelevant." That's entirely correct.

Now that COVID-19 vaccines are in surplus, there is no time like the present to protect yourself and your family against this scourge.