CDC deletes new guidance saying COVID-19 can spread beyond 6 feet

The new normal. A group walking in Boston Common last month.Craig F. Walker/Globe Staff

The US Centers for Disease Control and Prevention on Monday removed an update to its website that warned of “growing evidence” that the coronavirus can spread beyond 6 feet, particularly in indoor environments without good ventilation.

The warning was posted on a CDC web page as recently as Monday morning, prompting cheers from experts who believed it was high time for the agency to acknowledge that the virus can spread through aerosols, small particles that can linger longer in the air than larger droplets.

But by midday the CDC had returned to an earlier version of the web page.

A message at the top explained, “A draft version of proposed changes to these recommendations was posted in error to the agency’s official website. CDC is currently updating its recommendations regarding airborne transmission of SARS-CoV-2 (the virus that causes COVID-19). Once this process has been completed, the update language will be posted.” Asked for comment on the website changes, a CDC spokeswoman e-mailed the same text.

Jay Butler, the CDC’s deputy director for infectious disease, told The Washington Post, “Unfortunately an early draft of a revision went up without any technical review,” he said.

“We are returning to the earlier version and revisiting that process,” Butler said. “It was a failure of process at CDC.”

The update that was deleted said the virus “most commonly spreads” between people who are within about 6 feet of one another, but it also added that the spread comes “through respiratory droplets or small particles, such as those in aerosols, produced when an infected person coughs, sneezes, sings, talks, or breathes. These particles can be inhaled into the nose, mouth, airways, and lungs and cause infection. This is thought to be the main way the virus spreads.”

“It is possible that COVID-19 may spread through the droplets and airborne particles that are formed when a person who has COVID-19 coughs, sneezes, sings, talks, or breathes," the deleted post said.

"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). In general, indoor environments without good ventilation increase this risk,” the deleted post continued.

“Airborne viruses, including COVID-19, are among the most contagious and easily spread,” the deleted post said.

The deleted language has now been replaced by what appears to be the original language, which said the virus spreads, “Between people who are in close contact with one another (within about 6 feet) ... Through respiratory droplets produced when an infected person coughs, sneezes, or talks. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs.”

CNN reported that the update to the page was made on Friday, meaning it lasted through the weekend.

A number of experts had hailed the update as a sign of progress before it was removed by the CDC.

Joseph Allen, a professor at the Harvard T.H. Chan School of Public Health and director of the school’s Healthy Buildings Program, for example, on Twitter praised the update as a “key win” in a battle experts have been fighting since February to get aerosol transmission recognized.

After the update was deleted, Allen posted that there was a “dangerous game being played that is jeopardizing the lives of an already confused public.”

“For a weary public,” Allen tweeted, “As latest CDC debacle works itself out, let’s be clear about 2 things: --> Aerosol transmission is happening --> This means that in addition to steps you are already taking (masking/handwashing/distancing), add ventilation and filtration. The rest is games.”

Dr. Abraar Karan, a physician at Harvard Medical School working on the COVID-19 response in Massachusetts, also lauded the update. After it was removed from the site, he tweeted, “One of the big issues w/ the CDC posting this draft ‘in error’ is that science communications/public trust are *critical* — more than almost anything else we have in terms of mobilizing the public. And w/ a backdrop of messy politics, it casts this even further into question.”

Dr. Howard Koh, a Harvard professor who served as an assistant health and human services secretary in the Obama administration and before that as Massachusetts public health commissioner, said in a statement that “inconsistency in this administration’s guidance on COVID-19 has severely compromised the nation’s trust in our public health agencies. During the greatest public health emergency in a century, trust in public health is essential – without it, this pandemic could go on indefinitely. To rectify the latest challenge, the CDC must acknowledge that growing scientific evidence indicates the importance of airborne transmission through aerosols, making mask wearing even more critical as we head into the difficult fall and winter season.”

He said he was “extremely concerned about this administration’s attempts to pressure and push aside our nation’s top public health agencies at a time we need them most."

Monday’s reversal was the latest in a series of episodes that have raised questions about the independence of US health agencies at a time when doctors, disease experts and voters have become more concerned about political interference muddling public-health messaging.

In late August, the CDC quietly modified its coronavirus testing guidelines to exclude people who did not have symptoms of COVID-19 even if they had been recently exposed to the virus.

The move caused an uproar, and was followed by the New York Times reporting that the recommendation came from political appointees in the Trump administration and skipped the agency’s usual rigorous scientific review. The CDC changed course again on Friday, telling asymptomatic people who have had close contact with an infected person, “You need a test.”

Material from Globe wire services was used in this report.