Drosten, of the Charité in Berlin, suggested shortening the quarantine period for people suspected of having Covid-19 on his NDR podcast, the Coronavirus Update, which has returned after a summer break.

Currently people have to isolate at home for 14 days if there's a risk they could have the infection. But Drosten said research shows that people are no longer infectious after five days.

“There's already, let's say, a steep thesis, that after five days we say the infectious period is actually over,” said Drosten.

He said authorities needed to consider how long quarantine periods should last so that they don't turn into lockdowns.

“What can you do in reality so that you don't have a de facto lockdown?” he said. “It's no use having all kinds of school classes, all kinds of workplaces under weeks of quarantine.”

Drosten also suggested that the five days should not be “wasted” on being tested. Instead, people should only be tested after the five days have elapsed to see whether they were infected, and are still infectious.

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Drosten 'confident' coronavirus patients get immunity

The virologist also said he considered the confirmed cases of people getting secondary coronavirus infections to be a rarity. In his opinion, the vast majority of people who have survived Covid-19 are protected against getting it again.

“It's all just attention-grabbing,” Drosten said about a study published in Hong Kong with extensive publicity about the world's first proven re-infection of coronavirus.

At least for the duration of the current pandemic, immunity should continue, the virologist said. “I am very confident about this.”

In exceptional cases, renewed contact with the virus could possibly lead to a new surface infection, but this is unlikely to result in severe pneumonia. Due to the lower virus concentration in such cases, no more infection chains would likely develop.

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The cases of people becoming infected again would probably be epidemiologically insignificant in terms of their spread and danger, he said.

Scientists would report such cases in their communication report, the media would pick up on it and ask numerous questions about it, for example regarding immunity or the effectiveness of vaccines. “This does not describe the medical reality and the standard case,” Drosten said.

Face masks are 'complex'

Meanwhile, Drosten described the wearing of masks as a “complex issue”.

While “the moist pronunciation”, i.e. droplets, is intercepted by so-called 'everyday community masks', the situation is different with aerosols spread through the air.

The aerosols that are considered crucial for infection spreading are so fine as droplets “that they do not get caught in the material of an ill-fitting mask”.

“This weakness of the masks clearly exists,” said Drosten.

Drosten nevertheless strongly promoted the wearing of the masks with two examples: if you meet an infected person in the supermarket, for example, you won't be hit directly by the aerosol if both wear a mask.

Another example could be a colleague with bad breath. “With bad breath, these are aerosols,” he said. If two colleagues meet without a mask, the other one notices the bad breath – but not with a mask, proving they are useful.