The change of season or weather did not seem to be affecting the spread of COVID-19, and the pandemic could come as "one wave" instead of multiple waves like influenza, a World Health Organization (WHO) expert said on Tuesday.

"People are still thinking about seasons. What we all need to get our heads around is this is a new virus and... this one is behaving differently," said Dr. Margaret Harris, a WHO communications officer, at a virtual briefing in Geneva.

She said the season and weather did not seem to be affecting the spread of COVID-19. Rather, it was people gathering and not observing distance that had an effect on the virus spread. And as a later flu season is expected in the southern hemisphere, everyone is encouraged to get vaccinated against flu.

According to the expert, the COVID-19 was a new respiratory virus which has been behaving differently and not necessarily changing with the seasons. She said that WHO was not defining the pandemic in waves as it was all one wave, with its ups and downs, and the common task was to flatten it.