A Hong Kong man has caught coronavirus for a second time, leading experts to suggest that immunity to the virus post-diagnosis could be short-lived and that COVID-19 could be immune to any vaccine.
Genetic sequencing by researchers at the University of Hong Kong established that the second infection in the otherwise healthy 33-year-old male was caused by a different strain of the virus four months after he had recovered from an initial bout of COVID-19.
They had hoped that the man’s immune system would still have recognised and fought off the virus but it did not.
Dr Kelvin Kai-Wang To said anyone who has recovered from COVID-19 should not assume they were then immune to the virus.
“Our findings suggest that COVID-19 may persist in the global human population, as is the case for other common-cold associated human coronaviruses, even if patients have acquired immunity via natural infection,” Dr Kai-Wang To said in a statement.
He said anyone reinfected with COVID-19 should still be offered vaccination if and when it became available, and should also comply with mask-wearing and social distancing restrictions.
“This is the world’s first documentation of a patient who recovered from COVID-19 but got another episode of COVID-19 afterwards,” the university researchers said in a statement.
It’s believed the patient was unaware he had caught the virus a second time after returning home to Hong Kong from Spain on a flight via the UK.
His second infection was detected on entry to Hong Kong on 15 August. He was taken to hospital, where he stayed until he was given the all clear – remaining symptom-free for the entire period.
The incident followed his initial infection in March, where he reportedly suffered a fever, cough, sore throat and headache for several days.
The researchers say they are certain this is a case of reinfection and not of the virus lingering in the body.
They said the sequencing showed that the man’s virus was similar to the strain circulating in Europe.
Meanwhile the World Health Organisation (WHO) has cautioned against a rush to any conclusions about immunity in regard to repeat infections of coronavirus.
They said that ongoing studies tracking patients who had recovered from COVID-19 would help reach more definitive conclusions.
The WHO also noted that the man’s second infection was milder than his first, indicating that his immune system was seen to be providing some level of protection against the virus.
“There’s been more than 24 million cases reported to date,” Maria Van Kerkhove, a coronavirus expert at the WHO said yesterday.
“And we need to look at something like this at a population level.”