GENEVA, Feb. 27 (Xinhua) -- The extensive studies conducted in China and other places do not suggest that asymptomatic people are the driving force behind the COVID-19 epidemic, Michael Ryan, executive director of the World Health Organization's (WHO) Health Emergencies Program, said here on Feb 27.

The vast majority of transmissions occur from symptomatic individuals to other individuals, Ryan said at a daily briefing, stressing that persons showing no symptoms are not the major factors in the COVID-19 outbreak, even if scientifically someone can be infectious before the symptoms appear.

In response to a question from Xinhua about mask wearing, Ryan said that the WHO respects people who take action to protect their health, adding that "we try to tell people how to do it properly, and what else they need to do."

Maria van Kerkhove, technical lead for the WHO's Health Emergencies Program, said that according to WHO guidance, people are recommended to wear surgical masks to prevent transmission to someone else if they themselves have respiratory signs and illness symptoms.