“It’s a really important milestone. There’s still a long way to go, though.”
That’s the view of Prof Sarah Gilbert, one of the co-authors of a major study which has found a University of Oxford coronavirus vaccine is safe and induces an immune reaction.
Oxford scientists behind the trial have said the preliminary results are “very encouraging”, while Boris Johnson has said it is an “important step in the right direction”.
However, in a briefing following the release of the study on Monday, experts also sounded the need for caution. Here are three reasons...
1. Need to test older age groups
The trial included 1,077 healthy adults, aged 18 to 55 years, with no history of COVID-19. The average age of participants was 35.
Prof Gilbert told the briefing: “We still need to see how the vaccine performs in older people who are more at risk of severe disease than the people we vaccinated in this study. So that’s the subject of future work.”
The authors have also noted the need to confirm their findings in ethnically and geographically diverse populations: in the trial, 91% of participants were white.
2. Still don’t know if the vaccine will protect people
Monday’s positive results centred around immune response, but further testing is needed to see if the vaccine can effectively protect against infection.
Prof Gilbert explained at the briefing: “The vaccine is inducing the kind of immune responses that we think are associated with protection against coronavirus, and we are very pleased to see that.
“The difficulty we have, and that all vaccine developers have in trying to make a vaccine against this particular virus, is we don’t know how strong that immune response needs to be.
“So we can’t say, just by looking at the immune responses, whether this is going to protect people or not. The only way we are going to find out is by doing the large phase three trials.”
The ongoing phase three trials, to see if vaccines effectively protect against the virus, are taking place in the UK, Brazil and South Africa.
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3. Need direct comparisons
Governments around the world are keenly following the results of numerous vaccine trials in a bid to stem the pandemic.
Prof Andrew Pollard told the briefing more comparative data is needed.
“More quantitative comparability is needed between different vaccines. It’s hard for us to compare our vaccine results to other people’s vaccines.
“We would really like to see different vaccines being tested in the same lab by the same people so the world has a really direct comparison of the forms of different vaccines.”