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Explainer: Coronavirus reappears in discharged patients, raising questions in containment fight

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Explainer: Coronavirus reappears in discharged patients, raising questions in containment fight

By David Stanway, Kate Kelland

 

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FILE PHOTO: A general view of building A3 of the Shanghai Public Clinical Center, where the coronavirus patients are quarantined, in Shanghai, China February 17, 2020. Noel Celis/Pool via REUTERS

 

SHANGHAI/LONDON (Reuters) - A growing number of discharged coronavirus patients in China and elsewhere are testing positive after recovering, sometimes weeks after being allowed to leave the hospital, which could make the epidemic harder to eradicate.

 

On Wednesday, the Osaka prefectural government in Japan said a woman working as a tour-bus guide had tested positive for the coronavirus for a second time. This followed reports in China that discharged patients throughout the country were testing positive after their release from the hospital.

 

An official at China’s National Health Commission said on Friday that such patients have not been found to be infectious.

 

Experts say there are several ways discharged patients could fall ill with the virus again. Convalescing patients might not build up enough antibodies to develop immunity to SARS-CoV-2, and are being infected again. The virus also could be “biphasic”, meaning it lies dormant before creating new symptoms.

 

But some of the first cases of “reinfection” in China have been attributed to testing discrepancies.

 

On Feb. 21, a discharged patient in the southwestern Chinese city of Chengdu was readmitted 10 days after being discharged when a follow-up test came back positive.

 

Lei Xuezhong, the deputy director of the infectious diseases centre at the West China Hospital, told People’s Daily that hospitals were testing nose and throat samples when deciding whether patients should be discharged, but new tests were finding the virus in the lower respiratory tract.

 

Paul Hunter, a professor of medicine at Britain’s University of East Anglia who has been closely following the outbreak, told Reuters that although the patient in Osaka could have relapsed, it is also possible that the virus was still being released into her system from the initial infection, and she wasn’t tested properly before she was discharged.

 

The woman first tested positive in late January and was discharged from the hospital on Feb. 1, leading some experts to speculate that it was biphasic, like anthrax.

 

A Journal of the American Medical Association study of four infected medical personnel treated in Wuhan, the epicentre of the epidemic, said it was likely that some recovered patients would remain carriers even after meeting discharge criteria.

 

In China, for instance, patients must test negative, show no symptoms and have no abnormalities on X-rays before they are discharged.

 

Allen Cheng, professor of infectious diseases epidemiology at Monash University in Melbourne, said it wasn’t clear whether the patients were re-infected or had remained “persistently positive” after their symptoms disappeared. But he said the details of the Japan case suggested the patient had been reinfected.

 

Song Tie, vice director of the local disease control centre in southern China’s Guangdong province, told a media briefing on Wednesday that as many as 14% of discharged patients in the province have tested positive again and had returned to hospitals for observation.

 

He said one good sign is that none of those patients appear to have infected anyone else.

 

“From this understanding ... after someone has been infected by this kind of virus, he will produce antibodies, and after these antibodies are produced, he won’t be contagious,” he said.

 

Normally, convalescing patients will develop specific antibodies that render them immune to the virus that infected them, but reinfection is not impossible, said Adam Kamradt-Scott, a specialist in infectious diseases at the University of Sydney.

 

“In most cases though, because their body has developed an immune response to the first infection, the second infection is usually less severe,” Kamradt-Scott said.

 

Other experts have also raised the possibility of “antibody-dependent enhancement”, which means exposure to viruses might make patients more at risk of further infections and worse symptoms.

 

China has so far discharged 36,117 patients, according to data from the National Health Commission released on Friday, which represents almost 46% of the total cases on the Chinese mainland. If the 14% rate of reinfection is accurate and remains consistent, it could pose a wider health risk.

 

“I would say that it is less about if it is possible that re-infection can occur than how often it occurs,” Cheng said.

 

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-- © Copyright Reuters 2020-02-28

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Or perhaps their testing is inadequate,

 

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Or, there are several strains in circulation already.

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2 hours ago, snoop1130 said:

Experts say there are several ways discharged patients could fall ill with the virus again. Convalescing patients might not build up enough antibodies to develop immunity to SARS-CoV-2, and are being infected again. The virus also could be “biphasic”, meaning it lies dormant before creating new symptoms.

hmm; which sums to 'we don't really know'; how comforting

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36 minutes ago, car720 said:

I think I will rename this to Millenial Boomer Virus.  Designed by Millenials to get rid of Boomers.

After mutating, the Spanish flu killed mostly people in their 20s and 30s, old people had much higher survival rates.  So we older folk must mutate this one to wipe out millennials. Eat weird food or vape a lot.  They'll call it the millennial boomerang virus.

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Just maybe this is the BIG ONE but we don't know that yet.

 

Fear not though, "it's totally under control".

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16 hours ago, bkk6060 said:

Interesting.

Sounds like Herpes virus?

It breaks out, goes away, but stays in your system for life with future breakouts.

If that is in fact the case with this the world is indeed in a heep of trouble.

I read some hypothesis that since antiviral are used the body immune system did not develop adequate immunity since most of the work is done by the medication. Even if the body developed immunity in the case of SARS for example some study found that it only last about 6 months. 

Edited by Tayaout
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1 hour ago, Tayaout said:

They are talking about small point like mutations which are common but don't change virus properties. They use these as a marker to track where and how fast it spreads. This was done in China. From your link:

 

"... mutation has occured and this discovery will allow to reach(?) the genetic code of the virus, its specific characteristics in order to find out the time and spread speed of the virus."

 

More dangerous mutations are often caused by recombination, big chucks getting swapped around and mixed up. But that is a rarer event but can easily happen at the pandemic level.

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Yeah  - so, basically, they don't have a clue. What I can say is that China isn't closing down cities for nothing. Wait till it hits the US. That's gonna be interesting.

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this is next in Thailand starting tomorrow:

 

"The announcement empowers officials to order people suspected of being infected with Covid-19 to undergo treatment and put them in quarantine, and to close venues affected by the coronavirus, among other measures."

 

https://thethaiger.com/news/national/new-confirmed-patient-brings-total-to-42-health-ministry-announce-tough-new-measures

 

Edited by NCC1701A

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