British scientists racing to develop the world’s first Covid-19 vaccine have accidentally given clinical trial participants the wrong dose.
The mistake will be a huge embarrassment for the Oxford Covid-19 vaccine trial viewed as being in pole position to produce the first jab.
The first of 30 million doses for Brits had been expected to be approved as soon as September.
Oxford University insists “no pause to the study is required” after a smaller dose was administered.
The trial is the focus of scientists around the globe after it’s leaders took the unusual step of announcing before human trials that they were “80% confident” the vaccine candidate would work.
A working vaccine is the world’s main hope to resume normal life.
Leading virologists told of their surprise at such a “simple error” with some fearing it could affect the trial results.
Prof Ian Jones, Professor of Virology at the University of Reading, said: “Under-dosing is going to impact upon the clarity of the trial.
“I’m very surprised and it’s very disappointing for them to find this and have to report it. I just hope they still get sufficient data to make it worthwhile.”
Leading UK virologist Prof Ravi Gupta, of Cambridge University, said: “It is fairly unusual for this to happen.
“There can be issues when things are done quickly under lots of pressure that mistakes are made.”
Thousands of jobs are riding on how quickly the UK can roll out an effective coronavirus vaccine and fully reopen the economy.
Oxford has been backed by £65 million in UK Government funding and has teamed up with pharmaceutical giant AstraZeneca to manufacture its vaccine candidate.
The Mirror can reveal the mistake as Italy, Germany, the Netherlands and France sign an agreement to pay £675 million for 300 million doses.
The university has now checked with the Medicines and Healthcare products Regulatory Agency (MHRA) about the changed dose.
Despite the error a spokesman insisted the dosages were safe and the clinical trial was “progressing well”.
In a statement to the Daily Mirror it said: “The dose for the first part of the Phase 2/3 trial has been measured using one type of scientific test, and we are now switching to another way of measuring the dose which will give a slightly higher dose, that is similar to that used in our earlier Phase 1 trial.
“There is no concern about the change in dose and no pause in the study required by the UK regulator, MHRA.”
The trial vaccine has now been given to 2,000 participants so far. The university did not say how many had been given the wrong dose but it is understood they will be written to and notified.
The statement continued: “We monitor all trial participants very closely during the trial, assess regularly for Covid-19 and we are collecting blood samples to measure the immune response.”
Promising news about the Oxford trial helped AstraZeneca’s share price soar to a record high recently. It came as a merger with rival pharma giant Gilead was being touted.
There are currently 10 vaccines in human clinical trials worldwide according to the World Health Organisation.
The Oxford trial is the only one in Europe with five in China and four in the US.
US scientists have been critical of the Oxford team for the claim that they were 80% confident their vaccine would succeed at the beginning of human trials.
Dr William Schaffner, an infectious disease expert at Vanderbilt University Medical Center and adviser to the US Government had said he “sat straight up” when he read it.
“We don’t usually see that in public pronouncements,” he said.
“Some of us in the scientific community here in the US have been a little surprised at the sprightly competitiveness of some of the comments from our colleagues at Oxford.”
Dr Paul Offit, of the University of Pennsylvania, also said: “At this point the Oxford researchers have no idea whether they have something or not.”
The vaccine – called ChAdOx1 nCoV-19 – was first given to 500 healthy adults in April in the first stage to see whether it was safe.
The next stage of the trial involving 2,000 people at sites around the UK is to test whether it works.
Participants are given a jab and then given regular tests to see if they have Covid-19.
At the end of the trial scientists will compare those given the vaccine to those given a placebo and evaluate whether it protected the vaccine group from contracting the virus.
Prof Jones added: “Clearly there was a lot of activity around this vaccine being scaled up in to clinical trials and because of that a simple error could be made.
“The phase two is to see whether the vaccine induces antibodies which would be potentially protective.
“If you give participants less than the required dose you may get a negative answer, when actually the vaccine might be in that it was just they didn’t get enough of it.”
Prof Gupta added: “In this case you have a vaccine that we don’t know works and part of the trial is to measure the immune response.
“The numbers [involved in the trial]are so large I wouldn’t think it would make a big impact but they may have to recruit more participants to achieve the original aims.”