A visitor walks past an illuminated coronavirus model as he visit the "Mini-Worlds on the Way of Illumination" exhibition during the Light Festival preview at the Botanical garden in Paris, France, November 12, 2022. (Photo:REUTERS)

The Geneva-based UN health agency released a technical document on the topic on Thursday. It said it was the first step towards working out how to better prevent this kind of transmission, both for existing diseases like measles and for future pandemic threats.

The document concludes that the descriptor "through the air" can be used for infectious diseases where the main type of transmission involves the pathogen travelling through the air or being suspended in the air, in line with other terms such as "waterborne" diseases, which are understood across disciplines and by the public.

Almost 500 experts contributed to the definition, including physicists, public health professionals and engineers, many of whom disagreed bitterly over the topic in the past.