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Infectious Diseases

Updated 13 March 2020

Can you spread coronavirus even after your symptoms have disappeared?

Even though 80% of coronavirus cases are mild and treatable, experts warn that the spread of the virus is still a matter of concern, particularly as it may linger in the body long after symptoms have disappeared.

The World Health Organization (WHO) recently reported that, even though Covid-19 virus should be taken seriously, 80% of the cases are mild and completely treatable.

However, a small study from China now suggests that the new coronavirus may linger in the body for at least two more weeks after the symptoms of the disease have disappeared.

This is no reason for panic according to experts. There are many viruses that can still linger in the body after symptoms have cleared, and it seems that the patients are less contagious post-symptom than they were before they started showing symptoms.

According to Krys Johnson, an epidemiologist at Temple University’s College of Public health, the findings are not entirely bad news. “Viruses that tend to hang around in people’s systems also tend to be the viruses that the body develops a strong immunity response against,” he told Live Science.

What did the research entail?

The new study was published in the journal JAMA. The researchers followed four medical professionals between the ages of 30 and 36 who developed the Covid-19 virus and were treated at Wuhan University’s Zhongnan Hospital.

All the patients completely recovered after the illness and only one was hospitalised during the illness.

The patients were treated with the existing antiviral oseltamivir (also known as Tamiflu), which is usually used to treat influenza. After their symptoms cleared up, they were considered recovered and they tested negative for the Covid-19 virus twice on two consecutive days.

The patients were still ordered to quarantine themselves at home for five days. They continued to undergo swabs for the Covid-19 virus after five days for up to 13 days after recovery. On every test day between day five and day 13, the tests were, however, positive.

"These findings suggest that at least a proportion of recovered patients still may be virus carriers," the researchers wrote. 

Can you catch the Covid-19 virus twice?

At the same time, Japan reported a case of someone who recovered from the Covid-19 virus, only to become ill and test positive for the virus for a second time.

Experts were not clear on this case – some reckon that the patient caught a new version of the virus. Others tend to think that the patient’s own system didn’t fight off the virus completely, and it replicated inside the lungs again, causing symptoms for a second time.

Other viruses that linger

As mentioned before, it’s not new for viruses to linger in the body at low levels after recovering from symptoms. Ebenezer Tumban, a virologist at Michigan Tech University, mentions the Zika and Ebola virus as examples.

Tumban reckons that the Covid-19 virus in the patients started to replicate at a low level after the antiviral medication was stopped. As the virus was low level, there was not enough of it to cause symptoms again, and the patients were not even likely to be very contagious.

"They should be careful in the household setting not to share drinks and make sure they're washing their hands frequently," she said. "But if they're just a carrier, they shouldn't be able to transmit outside of that close contact of shared beverage and food,” stated Johnson.

READ | What is the difference between Covid-19 and coronavirus?

READ | Coronavirus 101 - what you need to know 

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