Scientists in Hong Kong have warned people who have contracted the coronavirus they are not “immune for life” because of different strains of the virus now circulating. The warning comes after a man was found to have caught two different strains of COVID-19 in March and August, sparking concerns any vaccine developed in the coming months may not be effective. Speaking to the Today programme, Prof Hung from the University of Hong Kong said: “Even though you have an infection before, it doesn't mean you are immunised for life.
“You are still at risk of having a second, or even a third infection.
“As a result, vaccination is very important and also the infection control measures, including masking and also social distancing still remains really important.”
Professor Peter Openshaw, a member of the Government's scientific advice team, said the re-infected man had an “unusually low” antibody response.
Prof Openshaw said: “The second infection was only picked up on airport screenings and he actually didn't have any symptoms.
“So it might have been that he had some protection against the more severe respiratory-tract form of the disease.”
Trials of a new vaccine developed at the University of Oxford in partnership with AstraZeneca have continued as researchers seek to build a team of 50,000 people to test the jab.
Prof Andrew Pollard, the Director of the Oxford Vaccine Group, echoed Chief Medical Officer Chris Whitty when suggesting caution should prevail before launching a vaccine in the coming months.
Prof Pollard said: “It could as long as the winter for, first of all, demonstrate a vaccine is safe and then to work through the process of regulators looking very carefully to make sure everything has been done correctly.
He continued: “And so if you've got a very, very rare disease, you need an enormous trial size, in order to be able to show whether the vaccine works.
“But in a situation like that at the moment depending on which region or country you are in, the size of the trial could be smaller or bigger just depending on how many cases are happening in that community at the time.
“There are a number of trials that we're running from Oxford here in the UK, in Brazil, and also in South Africa, and the combined size of those three trials together is around about 20,000 people, and AstraZeneca are moving forwards in their trials in the US, hoping to start enrolling 30,000 people.
“So within the trials of the vaccine that was developed here at Oxford University, we'd expect to have perhaps 50,000 or more people in the trials in total.”