The U.S. Centers for Disease Control and Prevention (CDC) recently published a new guideline, recognizing that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can spread via aerosols. Now, the health agency takes back its statement by deleting the updates published on Sept. 18.
Transmission electron micrograph of SARS-CoV-2 virus particles, isolated from a patient. Image captured and color-enhanced at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Maryland. Credit: NIAID
The first update on the page said that the coronavirus disease (COVID-19) most commonly spreads between people who are in close contact with one another and that the virus can spread through respiratory droplets or small particles, like those in aerosols that are produced when a person sneezes, coughs, speaks, sings, or breathes.
Further, the health agency said that these aerosols could hang in the air and inhaled into the nose, mouth, airways, and lungs. The CDC also acknowledged that there is growing evidence that droplets and aerosols can remain suspended in the air, which people can breathe in.
The airborne particles can travel beyond six feet, such as in situations of choir practice, fitness classes, and restaurants, particularly areas without adequate ventilation.
Many health experts cheered the CDC for recognizing the airborne spread of the virus. They said that the CDC’s update on Friday was one of the clearest acknowledgments by a public health organization that SARS-CoV-2 can spread through airborne particles and travel long distances.
However, just days after, the health agency retracted its first update and removed parts where it acknowledged the novel coronavirus’s airborne spread.
In the new update on the page on Sept. 21, the CDC removed the part where it says that SARS-CoV-2 can spread through airborne particles. Instead, the CDC said that COVID-19 is through to spread mainly through close contact from person-to-person.
“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 the airborne transmission of SARS-CoV-2 (the virus that causes COVID-19). Once this process has been completed, the updated language will be posted,” the agency said.
Further, the CDC said that the virus most commonly spread through respiratory droplets produced when an infected person coughs, sneezes, or talks. The agency removed the part that the virus can spread when infected people sing or breathe.
“These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs,” the health agency said, removing the part wherein it said that the droplets or virus particles could enter the body through the eyes.
The CDC still acknowledged that asymptomatic spread is present, wherein the virus can spread even if people have no symptoms.
“We are still learning about how the virus spreads and the severity of illness it causes,” it added.
No change in COVID-19 transmission guideline: WHO
Meanwhile, the World Health Organization (WHO) said that it would change its policy on the airborne transmission of SARS-CoV-2, noting that the primary mode of transmission of the virus is through respiratory droplets. However, Mike Ryan, WHO’s executive director of the emergency program, said that in crowded and closed spaces with inadequate ventilation, aerosol transmission can happen.
The move to acknowledge the possibility of airborne transmission was fueled by a group of more than 200 scientists across the globe, saying that there is evidence the virus can hang in the air and travel certain distances.
“There have been reported outbreaks of COVID-19 in some closed settings, such as restaurants, nightclubs, places of worship or places of work where people were maybe shouting, talking, or singing. In these outbreaks, aerosol transmission, particularly in these indoor locations where there are crowded and inadequately ventilated spaces where infected persons spend long periods with others, cannot be ruled out,” the WHO says on its website.
“More studies are urgently needed to investigate such instances and assess their significance for transmission of COVID-19,” it added.
The coronavirus pandemic has now reached 188 countries, infecting more than 31.4 million individuals and claiming at least 967,000 lives. The U.S. has the highest number of cases, with more than 6.88 million infections and more than 200,000 deaths. India and Brazil follow, with more than 5.56 million and 4.55 million cases, respectively.