We are now five months into the coronavirus pandemic and still there is debate over how the virus is transmitted.

The World Health Organization website states that “COVID-19 virus spreads primarily through droplets of saliva or discharge from the nose when an infected person coughs or sneezes.” And the CDC’s official guidance adds, “You may also be able to get it by touching a surface or object that has the virus on it, and then by touching your mouth, nose, or eyes.” But now there are questions about whether the virus lingers in the air and whether just breathing can spread the virus. The Washington Post writes:

More than 200 scientists from over 30 countries are urging the World Health Organization to take more seriously the possibility of the airborne spread of the novel coronavirus as case numbers rise around the world and surge in the United States.

In a forthcoming paper titled “It is Time to Address Airborne Transmission of Covid-19,” 239 signatories attempt to raise awareness about what they say is growing evidence that the virus can spread indoors through aerosols that linger in the air and can be infectious even in smaller quantities than previously thought.

But The New York Times reports that there are still a lot of questions about whether this is indeed the case:

Dr. Benedetta Allegranzi, the W.H.O.’s technical lead on infection control, said the evidence for the virus spreading by air was unconvincing.

“Especially in the last couple of months, we have been stating several times that we consider airborne transmission as possible but certainly not supported by solid or even clear evidence,” she said. “There is a strong debate on this.”

Watch more above from Reuters.