New CDC guidelines say coronavirus spreads through air. Then CDC deletes them.

Woman wearing her mask on her eyes.
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Once again, the U.S. Centers for Disease Control and Prevention (CDC) has provided guidance on COVID-19, only to contradict itself later. The CDC acknowledged what many scientists have been saying for months: that the novel coronavirus can spread through small airborne particles that can linger in poorly ventilated areas. Then a few days later, the agency walked it back.

The CDC updated their guidance on Friday (Sept. 18) to say that the virus can be spread through aerosols, or small particles that can linger in the air, according to CNN. The virus commonly spreads "through respiratory droplets or small particles, such as those in aerosols, produced when an infected person coughs, sneezes, sings, talks or breathes," the agency website read. If a person inhales these particles through the nose, mouth, airways and lungs, they can cause infection, according to the website. "This is thought to be the main way the virus spreads," they added.

"There is growing evidence that droplets and airborne particles can remain suspended in the air and be breathed in by others, and travel distances beyond 6 feet (for example, during choir practice, in restaurants, or in fitness classes)," the website said. "In general, indoor environments without good ventilation increase this risk." 

Related: Coronavirus Live Updates

In addition to wearing masks, washing hands, cleaning and disinfecting surfaces and staying at least 6 feet (1.8 meters) away from others, the CDC updated its recommendations to say that people should stay home, isolate when sick and "use air purifiers to help reduce airborne germs in indoor spaces," according to CNN.

But, these new guidelines were quickly taken down from the site and the CDC's current guidance on COVID-19 spread, as of Monday (Sept. 21) no longer acknowledges or even mentions airborne transmission. 

"A draft version of proposed changes to these recommendations was posted in error to the agency’s official website," the CDC said at the top of the page. " CDC is currently updating its recommendations regarding airborne transmission of SARS-CoV-2."Once that process is completed, the updated language will be posted, the update reads.

Regardless of the CDC's back-and-forth recommendations, mounting evidence suggests that the virus can spread through the air. 

Back in July, after being urged by hundreds of scientists, the World Health Organization acknowledged that the virus can spread through aerosols, according to The Washington Post. A number of studies support this conclusion, including one published in May in the CDC's Morbidity and Mortality Weekly Report  that found a person infected with SARS-CoV-2 spread it to 52 others at a choir practice in Washington.

This is the latest coronavirus guidance whiplash from the Centers for Disease Control and Prevention (CDC). Last week, the agency reversed controversial coronavirus testing guidelines that had suggested being exposed to a person with COVID-19 didn't necessarily warrant a test, Live Science previously reported.

Originally published on Live Science. 

Yasemin Saplakoglu
Staff Writer

Yasemin is a staff writer at Live Science, covering health, neuroscience and biology. Her work has appeared in Scientific American, Science and the San Jose Mercury News. She has a bachelor's degree in biomedical engineering from the University of Connecticut and a graduate certificate in science communication from the University of California, Santa Cruz.