The World Health Organisation says decisions on whether mass gatherings should go ahead must be made on a case-by-case basis.
The advice comes as the number of cases of Covid-19 across the world approaches 3.7 million.
More than 257,000 people have died, including 71,000 in the US.
Maria Van Kerkhove, from the W-H-O, says there's no clear answer on whether mass gatherings should go ahead at this time.
"Those decisions must be made on a case by case basis, because not all situations are the same, the areas in which they are carried out has different ventilation - some are indoors, some are outdoors.
"The same holds true for travel, the same holds true for holding meetings in some places.
"All of those decisions need to be taken on a case by case basis to determine if that meeting needs to take place."
