Victoria Premier Daniel Andrews says a coronavirus case reported on Tuesday is being treated as an extremely rare example of reinfection.
The male active case first tested positive in July but has since returned a second positive result three months later and was Tuesday’s sole new coronavirus case in Victoria.
His case was under review by an expert panel to determine whether his latest positive test was a result of viral shedding.
Mr Andrews said there was not enough evidence to conclude that was the case.
“The assumption is that they have it for a second time. If that is the case then that will be one of only a handful of those sorts of reinfection cases we have seen anywhere in the world,” Mr Andrews said.
According to The Lancet medical journal, there have been four cases of reinfections confirmed by viral genome sequences internationally up to September 14.
Mr Andrews downplayed the severity of the abnormal case, telling reporters the reinfection will likely be a “one-off”.
He did however say the case was “being managed very cautiously”.
Professor explains multiple reinfection possibilities
Biomedical Sciences Professor Sheena Cruickshank from the University of Manchester says the small number of reinfections “doesn’t necessarily mean that immunity is not occurring”.
She explained in The Conversation that testing issues or false-negative results could be responsible while saying reinfection can occur even in immunity however the worst effects are prevented.
For reinfections where worse symptoms follow the second time round, Professor Cruickshank says the body may not have mounted “a robust adaptive immune response first time round and that their initial infection was largely contained by the innate immune response”.
Another possibility is infection via differing viral strains.
“We are still learning about the immune response to COVID-19, and every piece of new data is helping us unpick the puzzle of this challenging virus,” Prof Cruickshank said.
“Our immune system is a powerful ally in the fight against infection, and only by unlocking it can we ultimately hope to defeat COVID-19.”
The health condition of the person responsible for Victoria’s believed reinfection has not been revealed by Victorian health authorities.
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