People in the United States and Europe are wrong not to wear face masks in public during the Covid-19 pandemic, according to the head of the Chinese Centre for Disease Control and Prevention.

“The big mistake in the US and Europe, in my opinion, is that people aren’t wearing masks,” Gao Fu, the agency’s director general, said in an interview with Science Magazine, one of the world’s leading academic journals.

“This virus is transmitted by droplets and close contact,” he said. “Droplets play a very important role – you’ve got to wear a mask, because when you speak, there are always droplets coming out of your mouth.”

Not everyone agrees with Gao’s assessment, however. The World Health Organisation (WHO), for instance, says that only people showing symptoms of infection or those caring for someone that has Covid-19 needs to wear a face mask.

The European and US disease control and prevention centres take a similar view to the WHO.

But Gao said people should err on the side of caution.

“Many people have asymptomatic or presymptomatic infections,” he said. “If they are wearing face masks, it can prevent droplets that carry the virus from escaping and infecting others.”

In its latest public advisory issued on March 22, the Chinese CDC said that people need not wear face masks when they are at home, in the open air, or in an environment where there is good airflow and no crowds. However, they should still wear them in the office, meeting rooms, lifts and on public transport.

According to figures from Johns Hopkins University in Maryland, as of Saturday, the US had almost 105,000 confirmed cases of Covid-19, more than any other country in the world.

As well as advocating the use of face masks, Gao called for more thermometers in public places in Europe and the US.

“Anywhere you go inside in China, there are thermometers,” he said. “You have to try to take people’s temperature as often as you can to make sure that whoever has a high fever stays out.”

He said that social distancing, restricting people’s movements, and isolating suspected and confirmed cases and those with whom they had been in contact were also important in combating Covid-19.

In January, Gao was part of the Chinese team that isolated and sequenced the novel coronavirus that causes Covid-19. He also co-authored two of the first papers on the subject, both of which were published in The New England Journal of Medicine.

Meanwhile, Gao said that in their bid to develop a vaccine and other drugs to fight Covid-19, Chinese scientists were currently carrying out tests on both monkeys and transgenic mice that have been injected with the ACE2 enzyme, the human receptor for the virus.

“I think there are at least a couple of papers coming out about the monkey models soon,” he said. “I can tell you that our monkey model works.”

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