You can catch Covid TWICE
Hong Kong man, 33, is first in the world proven to suffer virus for second time
THE first verified case of a patient being infected with coronavirus for a second time has been reported in Hong Kong.
A 33-year-old man who was struck down in March and recovered was found to be infected again this month.
Doubts were raised over previous reports of patients having Covid-19 twice, with the virus believed to have lingered in their bodies, making it look as if they were ill a second time.
However, the Hong Kong man has been proven to have had two different strains of the virus.
It means someone who has recovered from coronavirus may still pose a possible risk to others. Experts say it also means the concept of ‘herd immunity’ is no longer so certain.
It is the idea that when more than 60 per cent of the population have recovered from the virus – and have antibodies – others are less likely to get it.
Dr Kelvin Kai-Wang To, of Hong Kong University, said: ‘This man was hospitalised with Covid-19 in March after suffering symptoms like a cough and fever, then found to have it again at Hong Kong airport after returning from Spain. Many people think that when they have had the virus, they are then safe.
‘Our results show that is not the case and make it clear that people who have recovered should still be wearing masks and social distancing.’
The 33-year-old first fell ill on March 26, suffering three days of symptoms including a sore throat, headache, cough and fever. He was kept in hospital for more than two weeks, which was standard in Hong Kong to stop the virus spreading.
Then, 142 days later, he came home from a holiday to Spain, via the UK, and was found through a routine saliva test at Hong Kong airport to have the virus again.
Tests showed he had first been infected with a virus similar to the strains circulating in the US and UK in March and April, which may have been brought back to Hong Kong with repatriated citizens. His blood sample taken a day after he tested positive on August 14 showed evidence of a virus closely related to variants seen recently in the UK and Switzerland.
Other clues that the patient had been infected twice came from the rise in antibodies, apparently being produced by his immune system to fight a new version of the virus rather than the one it had seen before.
Previous evidence showed that a pregnant woman had kept the virus in her body for 104 days, but this is not thought to have been the case for the 33-year-old as levels of the virus and inflammation were high enough to indicate a new infection. His illness was also completely different the second time – when he suffered no symptoms at all.
The virus appears to cause a less severe illness the second time around, which may be because the body has immune cells which can fight it. Dr Jeffrey Barrett, of UKbased research body 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.’
He added: ‘It may be that second infections, when they do occur, are not serious.’
‘No symptoms in infection No2’