Man catches COVID-19 three times, baffling doctors
Prime Minister Scott Morrison keeps reminding Australians that a large proportion of those who tested positive for COVID-19 have recovered.
But what about reinfection?
A recent case - reported in a Chinese pre-peer-reviewed study on Wednesday - draws on the experience of a 68-year-old man who was reinfected twice after recovering from the virus.
The man (who was also suffering from heart problems) tested positive only to be retested after a few days' recuperation. His result was negative.
The man returned home only to be retested a little over a week a later. This time, the result was positive. Seven days later, he tested negative again. Then, four days after that, he tested positive again.
The man's yoyo diagnosis has experts concerned that even with a vaccine, the danger of reinfection could still be dangerously high.
The experience of the man in this case study may not be an isolated occurrence.
In February, reports emerged of a woman in Japan that appeared to have caught the virus again after initially recovering.
There have also been similar reports of possible reinfection emerging from China.
Australia's very own entertainment reporter Richard Wilkins was among those with fluctuating test results.
Wilkins took to Instagram to give his followers an update on his condition, warning everyone that while he tested positive multiple times, he still hadn't shown any symptoms.
"I've now returned a positive result THREE times," he wrote alongside a photo of him being tested in his home.
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So .... I’ve now returned a positive result THREE times... still can’t believe it as I still have ZERO symptoms. They tested me again today ,.. and hopefully will return a NEGATIVE result. Fingers crossed!!! The suggestion is .... that 3 days after the last symptom ...people should ‘assume’ that they’re over this thing ... and ‘proceed with caution’ ! I find this totally unacceptable and irresponsible! I completely understand the fact that the last thing the Health Dept wants to do is spend days retesting people like me... and God knows that I don’t want to soak up resources... but I don’t see how I can walk out my front door until I have a clean ‘bill of health’! I know the health system is fighting a huge battle ... and resources are stretched ...but in clear conscience ... I can’t put others at risk ... until I’m assured that I’m not POSITIVE anymore ! Love to all RW XX
Despite multiple reports of reinfection, some experts remain sceptical.
Professor Jimmy Whitworth from the London School of Hygiene and Tropical Medicine suggests these reports were likely due to the way the tests were conducted.
"There have been a few isolated examples where [reinfection] has been reported. That people were positive, then they were negative, then they were positive again," he said during a recent live Q&A session.
"It looks like, in the great majority of cases, this doesn't happen. That people get infected once.
"My suspicion is that those discrepant test results that we get are to do with, actually, the sampling. It's not straightforward to take a sample from the back of the throat and make sure you catch virus every time."
He said at the moment the predominant thinking is that most people become immune to the virus after getting it but it isn't clear how long that immunity lasts.
The potential of tests returning false positives must also be considered.
"Reinfection can't be ruled out, but it's possible the test is picking up lingering viral material in the cells, even after the virus has been killed," said Professor Jamie Triccas, head of infectious diseases and immunology at the University of Sydney.
These sentiments were echoed by Senior medical virologist with NSW Health Pathology, Professor William Rawlinson, who said it was too soon to say if reinfection was a feature of the virus.
"Once you have the infection, it could remain dormant and with minimal symptoms, and then you can get an exacerbation if it finds its way into the lungs," the NYU School of Medicine Professor Philip Tierno, told Reuters.
Originally published as Man catches COVID-19 three times