CDC removes guidance about airborne spread of the coronavirus

The Centers for Disease Control and Prevention abruptly removed information from its website saying that COVID-19 can spread through the air and that it may travel distances farther than six feet. It also removed statements saying that the virus usually spreads when people inhale particles produced by others.

The information was added in an update over the weekend and was taken down from a page called “How COVID-19 Spreads” earlier today. A banner at the top of the site now says that the information was posted in error.

Sen. Brian Schatz (D-HI) tweeted that the change is “very likely a scandal.”

Experts were thrilled to see the original update. Many have stressed for months that the virus can travel through tiny particles that float more slowly through the air, not just through the larger droplets that fall to the ground. That’s why both ventilating indoor spaces (to clear out residual virus) and wearing masks (to help block any exhaled particles) are just as, if not more, important than keeping six feet of distance.

But the CDC and the World Health Organization (WHO) have been reluctant to acknowledge the role that tiny airborne particles might play in disease spread. At the start of the pandemic, the agencies concluded that the coronavirus spread from person to person when they were in close contact with each other, through heavy, large droplets produced when someone who was sick coughed or sneezed. Research now indicates that there are other ways that the virus could be transmitted, including via aerosols. But the guidance at the CDC and WHO has not substantially changed, with the WHO wanting to see more evidence before making a ruling on transmission methods.

The removal of the guidance from the CDC website won’t change how many public health experts think about COVID-19 — they’ve been stressing the importance of ventilation for months anyway, even without the agency’s backing. It does impact the schools, businesses, and other organizations that lean on CDC recommendations to make decisions about what types of precautions they should take against a number of diseases, including COVID-19. If the agency stresses the importance of tiny droplets and encourages ventilation, it could change how those groups prepare to keep people safe.

The flip-flop over the past few days, even if it was accidental, also chips away again at trust in the agency. CDC guidance is usually reliable and is the first place doctors might turn to for help on how to handle a disease. During the pandemic, though, its guidances have been used as a political football: for example, The New York Times reported that the Department of Health and Human Services ignored scientific advice and published a guideline on the CDC website saying that people without symptoms did not need to be tested for COVID-19. That statement went against public health recommendations and was reversed.

The CDC website says that its recommendations around airborne transmission of the coronavirus are still being updated. It’s not clear when the final version might be posted.