CDC suddenly pulls guidance about coronavirus spreading through tiny aerosol particles

When the Centres for Disease Control and Prevention (CDC) updated its coronavirus guidance last week to say that Covid-19 spreads mainly through tiny droplets called aerosols — and not through the larger beads of spit and phlegm that enter the air from coughing and sneezing — outside health experts were relieved the organisation had finally come around to the general scientific consensus.

But on Monday, the CDC suddenly retracted that new guidance, saying “that does not reflect our current state of knowledge,” The Washington Post reported.

The yanked guidance had suggested that even staying six feet away from other people, especially indoors, does not protect you from Covid-19.

Aerosols are “thought to be the main way the virus spreads,” the guidance indicated.

“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 CDC’s update said.

“In general, indoor environments without good ventilation increase this risk,” it said.

Independent researchers and scientists unaffiliated with government have been saying for months that the evidence suggests the six-feet-of-distance rule is not enough and that aerosols are the primary transmitter of the disease that has killed nearly 200,000 Americans so far this year.

Informing the public about how Covid-19 is actually transmitted is key to helping Americans understand what precautions they should be taking to avoid catching it, scientists have said.

“It is critical to have a clear physical description of the ways in which Covid-19 is transmitted, so that individuals and institutions are able to visualize it and will understand how to protect themselves,” Jose-Luis Jimenez, a chemistry professor and aerosols researcher at the University of Colorado, wrote in an article for Time last month.

“Contrary to public health messaging, I, together with many other scientists, believe that a substantial share of Covid-19 cases are the result of transmission through aerosols. The evidence in favor of aerosols is stronger than that for any other pathway, and officials need to be more aggressive in expressing this reality if we want to get the pandemic under control,” Mr Jimenez wrote at the time.

The CDC finally appeared to have caught up with the science last Friday by changing its guidance to reflect the threat posed by aerosols. Scientists had been pushing for the change for months.

“These particles can be inhaled into the nose, mouth, airways, and lungs and cause infection,” the updated guidance said of aerosols over the weekend.

Now, that update is nowhere to be found, prompting even more questions about the Trump administration’s politicization of US health organisations and information about the coronavirus.

Four former CDC directors wrote an op-ed for the Post in July claiming the president and others in his administration had made “repeated efforts to subvert sound public health guidelines” in the debate over opening schools for in-person classes this fall.

“Willful disregard for public health guidelines is, unsurprisingly, leading to a sharp rise in infections and deaths. America now stands as a global outlier in the coronavirus pandemic,” the former CDC directors wrote.