The World Health Organization on Thursday released new guidelines on the transmission of the novel coronavirus that acknowledge some reports of airborne transmission of the virus that causes COVID-19, but stopped short of confirming that the virus spreads through the air.

In its latest transmission guidance, the WHO acknowledged that some outbreak reports related to indoor crowded spaces have suggested the possibility of aerosol transmission, such as during choir practice, in restaurants or in fitness classes.

But the WHO said more research is "urgently needed to investigate such instances and assess their significance for transmission of COVID-19."