LONDON (AP) — The World Health Organization is acknowledging the possibility that COVID-19 might be spread in the air under certain conditions.

This comes after an open letter from more than 200 scientists published this week urging the agency to do so.

WHO has long dismissed the possibility that the coronavirus is airborne except for certain risky medical procedures, such as when patients are first put on breathing machines.

But it noted on Thursday that studies evaluating COVID-19 outbreaks in restaurants, choir practices and fitness classes suggested the virus might have been spread in the air.