Amidst heightened concern over COVID-19 reinfection, a case has now emerged in Kerala of a man testing positive for coronovirus three times. While the man tested positive on the RT-PCR (real-time polymerase chain reaction test), the question of whether this is a case of reinfection or merely viral shedding can be proved only by genome sequencing.
Savio Joseph, a 38-year-old man from Thrissur, returned from Oman in June after recovering from the infection for the first time. He was first infected in March, while working in Muscat. He then quit his job as a service supervisor at an event management firm and returned home as the pandemic worsened in Oman. â€śFour people who worked as my subordinate died due to the infection,â€ť Savio told TNM, recounting that his first bout of the disease was severe. â€śI thought that I would die,â€ť he said.
However, when Savio presented with symptoms of COVID-19 - fever, breathing difficulty and chest - in July, he went in for another test, which returned positive. Savio was admitted at the Thrissur Government Medical College Hospital on July 22 and was discharged on August 11.
â€śThe symptoms persisted. I still had breathing difficulty. I have been keen to find out why and so I quit my job to take care of my health. I was told by a doctor at the District Hospital in Thrissur that it could be fibrosis that may develop in COVID-19 survivors. The first time, I got pneumonia and later I was given medicines for bronchitis,â€ť he said.
With Savioâ€™s breathing difficulties persisting, he went in for an RT-PCR test less than a month later, which once again came back positive. He once again was admitted at the Thrissur Government Medical College Hospital on September 5 and was discharged a week later on September 11 based on antigen test which came negative.
Savioâ€™s repeated hospitalisation has meant losing out on precious family time. His wife, a nurse in Kozhikode, had delivered twin daughters in April. But owing to his illness, Savio has been unable to visit his family fearing the risk of infecting them.
Advising others not to let their guard drop amid the pandemic, Savio said, â€śDonâ€™t think that the infection wonâ€™t be repeated; it could, and I am the example.â€ť
Reinfection or viral shedding?
So what explains Savio testing positive for the novel coronavirus on three occasions?
Thrissur District Medical Officer Dr KJ Reena said that Savio was the first such case in the district. She, however, explained to TNM that the RT-PCR test would show a positive result if it detected dead virus cells, which are no longer infectious.
â€śWe canâ€™t say whether it was reinfection or viral shedding as itâ€™s a new virus and its behaviour is yet to be thoroughly studied. Maybe it is reinfection, or it is the dormant virus [particles] which was in his body,â€ť said Dr Reena.
On the question of why Savio tested negative before his discharge, she pointed out, â€śThe antigen or RT-PCR results could be negative because the virus may not have not been detected [by the testing kits] when immunity was high and more antibodies developed. But it might have detected [the virus] when the immunity was low which resulted in the COVID-19 positive.â€ť
Dr B Ekbal, who heads the state expert committee that advises the Kerala government on the coronavirus, also believed that Savio was a case of viral shedding rather than a case of reinfection. â€śIt could be a case of false positive. Viral shedding would keep on happening and if a person is tested again, the result may become positive. This is called viral litter, that canâ€™t be termed as COVID-19 as that person canâ€™t be infectious,â€ť he said. â€śThe test is absolute, but there could be false negatives and positives; studies have been done on reinfection by isolating thousands of cases. But it hasnâ€™t been proved,â€ť he added.
Viral shedding occurs when a virus replicates inside your body and is released into the environment.
A doctor who works closely with COVID-19 patients told TNM that whether Savioâ€™s case was one of reinfection or viral shedding can be found out only by genomic sequencing. â€śSuch cases have come to our notice; but that can be confirmed as reinfection only on the basis of genomic studies,â€ť he said.
Genomic sequencing is the process of determining the DNA sequence of an organismâ€™s entire genome at one time.
â€śReinfection is also common but in this particular case we are not able to say if it was so. For three to four months the PCR would show positive results even in the recovered patients. This is RNA shedding, not replication of the virus,â€ť said the doctor.
The worldâ€™s first case of reinfection was reported in Hong Kong in August. The case of reinfection was established by genome sequencing, wherein the 33-year-old man, who had recovered from COVID-19 in April, tested positive for a variant of the SARS-CoV-2 virus four months later. In India, two cases of reinfection have been established by genome sequencing in Greater Noida Two health workers, who were asymptomatic, tested positive over three months after their recovery from COVID-19.