We recognize that evidence is emerging in this regard and therefore we must remain open to this possibility and its implications, as well as the precautions to be taken, said Benedetta Allegranzi, a WHO official at a telematic press conference.

The possibility of airborne transmission in public places, especially crowded, cannot be excluded. However, the evidence must be gathered and interpreted, Allegranzi continued.

The person in charge advised an efficient ventilation in the closed places and the physical distance. When it is not possible, we advise the use of a mask, she said.

On Monday, a group of 239 international scientists urged the WHO and the international medical community to recognize possible airborne transmission of Covid-19, in an article published in the journal Clinical Infectious Diseases in Oxford.

The WHO, already criticized for being slow to advise the use of masks, was accused of not wanting to admit the evidence that points to an airborne spread of the new coronavirus, which has already killed more than 535,000 people in six months.

The institution insisted on Tuesday that the epidemic is accelerating, and we have not reached the peak of the pandemic, in the words of its director general, Tedros Adhanom Ghebreyesus.

Although the death toll appears to have stabilized globally, in reality, some countries have made significant progress in reducing the number of cases, while others continue to grow, he said at a press conference.