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Coronavirus still stumps experts on when human carrier turns infectious

  • Identifying how long it takes before carriers start to spread the virus could prove key to curbing the spread of Covid-19
  • Researchers are trying to determine whether it can be transmitted before carriers start to show symptoms

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Understanding the behaviour of the virus will help scientists develop a vaccine. Photo: Xinhua

Global health experts are divided on whether the coronavirus outbreak has peaked or worse is to come, but a more fundamental problem for front-line hospitals and laboratories is identifying when a person carrying the virus becomes infectious to others.

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Scientists say this could be a key to defeating the disease it causes, now officially known as Covid-19. In other words, knowing how it behaves allows for the development of counter strategies.

The ideal countermeasure is a vaccine, but because doctors are dealing with a previously unknown virus, infectious disease experts, including Professor John Nicholls from the University of Hong Kong, said it would take many months to develop and test a drug to fight it.

So scientists have focused on the incubation period of this virus – the length of time it takes between an individual being exposed to it and showing the pneumonia-like symptoms that characterise Covid-19.

The other question puzzling researchers is whether the virus can be transmitted before a carrier starts to show these symptoms.

A study published on Sunday by a team of Chinese researchers estimated the incubation period could last up to 24 days, much longer than the previous estimate of 14 days.

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