US Centers for Disease Control and Prevention (CDC) has now retracted its new guideline which said that aerosol transmission of coronavirus is possible. Experts fear that this might be due to political pressure and not scientific evidence. The retraction happened in the form of data removal from CDC website on Monday.
Why did the CDC change the guidelines regarding airborne transmission of COVID-19 once again?
— Dr. David Samadi, MD (@drdavidsamadi) September 22, 2020
On the previous Friday, CDC had updated its guidance on how coronavirus spreads. It included transmission through aerosol droplets. It means that it is possible for coronavirus to spread from a distance of more than 6 feet in rooms where there is little or no ventilation.
The CDC said the virus was known to spread “through respiratory droplets or small particles, such as those in aerosols, produced when an infected person coughs, sneezes, sings, talks or breathes.”
This update on Friday, was picked up by print media and was not announced by the health agency. After widespread reporting, on the following Monday the website removed the new guidelines and change the language and data on the page to what was before Friday.
The move comes with explanation by top CDC officials that the guidance on airborne transmission was in fact a “draft” which was posted on the site because of an error. They included in their stamen that CDC is still reviewing its guidance on airborne transmission of coronavirus. After the statement, the health agency denied any request for further comments.
The rollback of this guidance was met with criticism by both political and scientific community. Many have raised concerns that this step along with CDC going back and forth on its testing recommendations for asymptomatic people exposed to coronavirus has left the agency’s credibility in murky waters.
One way or another, we’re going to investigate it and find out. https://t.co/s8HUsU0MIK
— Congressman Raja Krishnamoorthi (@CongressmanRaja) September 21, 2020
I’ve seen some of these “changes” in guidelines occur first hand throughout the past 6 months-this is likely what happened: @CDCgov tried to warn & tell the truth, it didn’t fit the President’s narrative & someone got an angry call. This is so dangerous for the American people. https://t.co/AkePEccqrC
— Olivia of Troye (@OliviaTroye) September 21, 2020
“The latest example of a deeply broken Trump Administration response that sows confusion, fans the virus’s spread and costs Americans’ lives,” said House Speaker Nancy Pelosi.
She also added that people in United States “need to hear directly from the scientists about how the virus spreads and what precautions are necessary — not guidance that worries more about contradicting President Trump than keeping families safe.”
The guidance on aerosol transmission is very significant to control spread of the virus. Many countries have already included guidance regarding this subject in their official statements. These countries include Japan among many others.
New data has even shown that face shields are not even 100 percent effective in trapping respiratory aerosols. A computer stimulation using the world’s fastest supercomputer (Fugaku) has shown that almost 100% of airborne droplets of less than 5 micrometers in size escaped through plastic visors of the kind often used by people working in service industries. One micrometer is one millionth of a meter.
A simulation of Japanese supercomputer Fugaku shows that nearly all the aerosols are leaked when wearing only a face shield https://t.co/DiQrEZaWuy
— Natsuko Fukue (@natfukue) September 22, 2020
Also, separate data from a government institute Riken, has found that about half of larger droplets measuring 50 micrometers found their way into the air. This has led the senior scientists from both United States and United Kingdom to criticize placing insufficient emphasis on aerosol transmission and ventilation.
However, one supporter of the agency that has emerged is the senior scholar, Amesh Adalja, of the Johns Hopkins University Center for Health Security. He explains that it might be true that the agency posted the guidelines in error. According to him, the distinction between “airborne” and “aerosols” is complicated and somewhat semantic.
The “airborne” description is usually applied by infectious disease doctors to diseases like measles, which is far more contagious than COVID-19. That’s why public health officials have been more concerned with close person-to-person contact.