AstraZeneca and Oxford University say they are likely to carry out another trial on their coronavirus vaccine after a dosing error gave a surprise result.
Some people were given a half dose followed by a full dose, which improved the effectiveness of the jab and put it up to 90% protection.
AstraZeneca has insisted any additional trials would not hold up regulatory approval in any country, including the UK.
Professor Andrew Pollard, director of the Oxford Vaccine Group, told a press briefing last week the 90% effectiveness finding had already met the ‘necessary statistical evidence as required by regulators’.
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He said further evidence will probably be available next month but it is ‘a highly significant result even with the numbers that we have’.
The 90% effectiveness finding was based on a dosing regime given to 2,741 people. The other option, which involved two doses, was given to 8,895 people.
The overall efficacy from the two different dosing regimes in a phase three trial was announced at a combined figure of 70%.
Questions raised
It comes after US scientists have heavily questioned the Oxford injection this week.
Moncef Slaoui, the scientific head of the US’s operation to find supply vaccines – called Operation Warp Speed – claimed the half dose was only given to people aged 55 and under.
But the Oxford Vaccine Group have not disclosed anything like this. Results from an earlier phase two study published in The Lancet medical journal showed the vaccine produced a strong response in all age groups.
Other scientists raised concerns about a lack of detail in the results put out last week.
The New York Times reported AstraZeneca’s Menelas Pangalos had needed to defend the company’s handling of testing and its public disclosures.
Experts also pointed out how the two clinical trials in Britain and Brazil were differently designed, yet analysis was pooled from both.
They also say it is unclear how many coronavirus cases were found in each group of the trial.
John Moore, a professor of microbiology and immunology at Weill Cornell Medical College, told the New York Times: ‘The press release raised more questions than it answered.’
Mr Pangalos had said the half-dose finding ‘could end up being quite a useful mistake’, adding: ‘What is there to disclose? It actually doesn’t matter whether it was done on purpose or not.’
The effectiveness was found to be 62% in the trial group given two full doses, which is significantly lower than both the American Moderna jab and the German Pfizer jab, which were both found to give 95% protection.
Concerns have been raised however that although the Moderna and Pfizer injections prevent people from getting ill, they haven’t yet been tested for whether they actually stop Covid-19 spreading.
It comes as it was revealed today regulators have formally been asked to assess Oxford vaccine.
The move ‘marks a significant first step in getting the vaccine approved for deployment’ if it meets the necessary safety, efficacy and quality standards, the Department of Health and Social Care said.
It comes a week after the Medicines and Healthcare products Regulatory Agency was formally asked by the Government to assess the Pfizer vaccine.
Health Secretary Matt Hancock said: ‘We are working tirelessly to be in the best possible position to deploy a vaccine as soon as one is approved by the independent regulator the MHRA.
‘We have formally asked the regulator to assess the Oxford/AstraZeneca vaccine, to understand the data and determine whether it meets rigorous safety standards.’
The race continues to be the first in the world to approve a vaccine for coronavirus, with a Government source saying it’s a ’50/50 chance’ as to whether the UK or Germany will get there first – and it could come as early as next week.
Scientists said it is important to wait for the full Oxford dataset to be published before making any assumptions about the results.
Professor Chris Whitty, chief medical advisor to the UK Government, said at the Downing press conference last night: ‘The simple answer to this is there is always scientific debate about virtually everything.
‘The key thing from our point of view is to leave this in the hands of the regulator, the excellent MHRA regulator.
‘They will make an assessment with lots of data that is not currently in the public domain on efficacy and on safety and we will see the papers published in peer reviewed journals, which will allow us to make a decision about what needs to happen.
‘We need to allow that process to go forward. I think it’s always a mistake to make judgement early before we have enough information.’
A spokesperson for AstraZeneca said yesterday: ‘As the development of the vaccine was scaled up into the Oxford-sponsored Phase II/III trial, the measurement used for earlier trials was shown to over-estimate the strength of dose in the new larger batches, resulting in a half dose of the vaccine being administered.
‘This was reviewed by the independent Data Safety Monitoring Board and the UK regulator, both of whom approved the continuation of this dosing regimen and the regulator publicly confirmed that there was “no concern”.
‘All other regulatory authorities were informed that we would continue to monitor and study this cohort. Given the high efficacy we have now seen with the different dosing regimens, there is strong merit in continuing to further investigate these findings in order to establish the most effective dosing regimen.
‘We are in discussions with regulators around the world to evaluate these findings and we look forward to the publication of the peer-reviewed results, which has now been submitted to the journal.’
Oxford University said it would not comment ahead of the data appearing in a peer-reviewed publication.
The Oxford vaccine is only £2 to £3 per dose and can be more easily stored than vaccines from Pfizer and Moderna, which require sub-zero temperatures.
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