Scientists in Hong Kong have reportedly documented the first case of a healthy man in his 30s who became reinfected with coronavirus four and a half months after his first bout.
The report by the University of Hong Kong, due to be published in Clinical Infectious Diseases, says the man spent 14 days in hospital before recovering from the virus but then, despite having no further symptoms, tested positive for the virus a second time, following a saliva test during airport screening.
The scientists said the genome sequencing showed the two strains of the virus were ‘clearly different’, making it the world’s first proven case of reinfection.
However, the World Health Organization (WHO) warned that it was important not to jump to conclusions based on the case of one patient.
The BBC reported that experts said reinfections ‘may be rare and not necessarily serious’.
The report said the strongest immune response had been found in the most seriously ill patients among the more than 23 million who had been infected so far.
It was not clear, however, how strong this protection or immunity was, or how long it lasted.
The WHO said larger studies over time of people who had previously had coronavirus were needed to find out more.
Brendan Wren, professor of microbial pathogenesis, at London School of Hygiene and Tropical Medicine, said: ‘This is a very rare example of reinfection. And it should not negate the global drive to develop Covid-19 vaccines. It is to be expected that the virus will naturally mutate over time.’
Dr Jeffrey Barrett, senior scientific consultant for the Covid-19 genome project at the Wellcome Sanger Institute, said: ‘Given the number of global infections to date, seeing one case of reinfection is not that surprising even if it is a very rare occurrence.
‘It may be that second infections, when they do occur, are not serious – though we don’t know whether this person was infectious during their second episode.’
Meanwhile, the BBC reported that officials in South Korea, held up as a model for its response to Covid-19, said the country was on the brink of a new nationwide outbreak.
The latest outbreak, centred on a right-wing Presbyterian church, had spread to all 17 provinces throughout the country for the first time.
The report said one of the biggest concerns was that many of the far-right worshippers who were potentially infected believed the virus was planted as part of a conspiracy to close it down. Many were refusing to be contacted, let alone tested.
In South Africa, positive cases grew yesterday by 1 677 to a cumulative total of 611 450 (with 516 494 recoveries). Deaths rose by 100 to 13 159.
The highest tally of cases is in Gauteng (206 525), followed by KwaZulu-Natal (110 102), the Western Cape (104 667) and the Eastern Cape (85 240).