Chinese researchers claim they may have discovered a new mutated sub-type of the novel coronavirus which has a prolonged ability to infect others.
Experts found an unusual case of a middle-aged man with COVID-19 disease who was infectious for 49 days – a record length of time never reported before.
However, the man’s symptoms were mild and the researchers said he appeared to have formed a ‘dynamic balance’ with the virus.
The ‘chronic’ case indicates a strain which can spread among people for weeks, even if the host doesn’t show many symptoms.
It appears harder to shake off, too. The man needed to be injected with the blood of a COVID-19 survivor in order to recover.
Previous research showed that patients who survived the virus normally tested negative after 20 days, with the longest case at 37 days, with longer cases usually being more severe cases. The picture shows a medical worker looking at CT scans at Huoshenshan hospital in Wuhan
The study was published on March 27 on medRxiv, a preprint site for scientific medical papers. It means it hasn’t been scrutinised by other scientists yet.
The Chinese man, who has not been named, visited a hospital in Wuhan to have SARS-CoV-2 tests on February 8, 2020.
He stated that he had suffered an intermittent fever for around one week, but had no other common symptoms, such as a cough.
COVID-19 testing collected with swabs to the throat tested positive on days 17, 22, 26, 30, 34, 39, 43 and 49. It came back as negative on day 47, which may have been a fluke.
This suggests that the patient was ‘shedding’ the virus for 49 days, a scientific term describing how a person excretes the disease in their breathe or through sneeze and cough droplets.
Previous research shows that viral shedding lasts 20 days on average, with the longest case reported at 37 days.
The longer the duration of shedding, the more severe the outcomes tend to be, Dr Li Tan and colleagues said.
‘Interestingly, contrary to the conclusions above, we here reported one of the non-severe cases has the longest duration of viral shedding,’ the team said.
The researchers said this information could point towards a new mild sub-type of SARS-CoV-2. The picture shows medics using a bronchoscope to treat a coronavirus patient in Wuhan
Because the patient seemingly could not fight off the disease himself, he needed to be treated with a blood-based therapy being used in China and experimentally in the US and the UK.
He was given a plasma transfusion from a COVID-19 sufferer who had recovered and had virus-fighting antibodies in their blood.
The patient had some infected lesions to his lungs which disappeared shortly after he was taken to hospital.
The researchers said the case might be a ‘chronic infected case’.
Reports state one of the patient’s elderly female relatives also tested positive for COVID-19, with moderate symptoms.
Despite having pre-existing conditions – which would have made her vulnerable to serious complications – she reportedly recovered quicker recovery than average for her age.
The researchers said that this information could point towards a new mild sub-type of SARS-CoV-2, the name of the novel coronavirus.
It has lower toxicity, is not as infectious, but is harder to eliminate. It appears to affect both the young and the old.
Already, Chinese researchers have discussed the possibility of two major types of SARS-CoV-2, namely L subtype and S subtype.
L type is more prevalent consisting of approximately 70 per cent in all patients and is more likely to spread than S type, Chinese researchers found.
Dr Tan and colleagues said: ‘We cannot assure that Case 1-associated virus belongs to S type, mutated L type or a new subtype.
‘We cannot exclude an original new subtype that was not identified.’
They warned that other ‘chronic’ patients who maybe would not be treated because of their mild symptoms could continue to spread the infection and cause a fresh outbreak.
The case has featured in prominent Chinese media outlets and in international titles including the South China Morning Post.