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The top U.S. public health agency recently updated its public guidance on how the coronavirus spreads through the air – in tiny droplets and very small particles exhaled by others – and can be transmitted even at distances greater than six feet. 

The Centers for Disease Control and Prevention’s previous guidance said infections were acquired “mainly through close contact from person to person, including between people who are physically near each other (within about 6 feet),” but it did not specify the airborne threat of the virus.

On Friday, the CDC released its updated guidance, acknowledging that one of the ways people can get infected with the virus is by breathing in affected particles. It now explicitly states that airborne virus can be inhaled even when one is more than six feet away from an infected individual.

“COVID-19 spreads when an infected person breathes out droplets and very small particles that contain the virus,” the updated guidance reads. “These droplets and particles can be breathed in by other people or land on their eyes, noses, or mouth.”

The agency said people within six feet still are more likely to get infected, but the updated guidance reflects current knowledge about transmission and was “reformatted to be more concise.”

“Although how we understand transmission occurs has shifted, the ways to prevent infection with this virus have not,” the agency said in a statement. “All prevention measures that CDC recommends remain effective for these forms of transmission.”

As the pandemic unfolded last year, the CDC and the World Health Organization drew criticism from infectious disease experts who alleged the two agencies were overlooking research that suggested the potential airborne transmission of the coronavirus.

While W.H.O. eventually confirmed that there was “emerging evidence” that strongly suggested that people can catch the virus from droplets floating in the air, the CDC continued to believe that the primary means of infection was through “close contact, not airborne transmission.”

The CDC has previously come under fire for past revisions of its guidance. Last September, the agency stirred confusion when it posted — then abruptly took down — an apparent change in its position on how the coronavirus can spread from person to person through the air.

The removed post suggested that the agency, after months of saying little about aerosolized particles, acknowledged the virus can hang in the air and spread over an extended distance.

But officials at the time said it made “an honest mistake” when it posted the update that did not undergo a full review and approval process.

Then, last October, the CDC updated its guidance again to say that the coronavirus “can sometimes be spread by airborne transmission,” specifically in poorly ventilated indoor spaces.

While the new guidance finally highlighted the airborne threat of the coronavirus, the agency still says that breathing in the virus when people are far apart is “uncommon.”