The success of the vaccine being developed in Oxford, UK, is far from guaranteed, warns the project leader, Adrian Hill, who in an interview with The Telegraph launches an alert regarding possible exaggerated expectations about the vaccine. “There is a 50% chance that we will succeed and a 50% chance that we won’t get any results.” And one of the main obstacles to the investigation is “bizarre”, as the researcher acknowledges: the number of new infections in the UK is dropping too quickly.
“Right now, there is a 50% probability that we will not be able to get any results”, neither encouraging nor discouraging. Adrian Hill explains that the team of researchers he leads at the Jenner Institute is in a “race against time” and a “race against the disappearance of the virus”. The problem is that, if this rate of contagion continues to be less and less, this could mean that at some point there are not enough people to be able to test the vaccine called ChAdOx1nCov-19 (read Chaddox One).
This team of researchers went so far as to say that there was an 80% probability that an effective vaccine could be produced by September. But the virus is “disappearing” at such a fast rate, according to the researcher, that “we are in the bizarre situation that is wanting Covid to stay with us, at least for a little while longer“.
The vaccine was found to have excellent results in monkeys and there was a decision to move towards testing in humans. Although not always a valid indicator, the promising results with monkeys gave the Jenner Institute’s vaccine a “green light” to move more quickly to human trials. At However, people are not deliberately exposed to the virus (as was done with animals): the ethical rules of clinical trials require that the vaccine be applied to people who are already in environments where the virus is circulating.
But with contagion in a declining phase, researchers are worried about the validity of moving to the second and third phases, which are expected to involve testing more than 10,000 people, involving children and the elderly. If there is not a sufficiently prevalent virus circulation, it will be difficult to prove the vaccine’s effectiveness.
In the ongoing clinical trial, half of the 500 volunteers receive the vaccine for the new coronavirus, while the other half receive the meningitis vaccine. None of the groups will know which vaccine they received. Everyone is asked to make life normal. As people become infected with the new coronavirus, they will be subjected to the Covid-19 screening test. Then, when a sufficient number of volunteers have been infected, it will be up to mathematicians and epidemiologists to check in which group these people were included in the clinical trial.
“The goal is that all those infected with Covid-19 belong to the meningitis vaccine group,” explained Sarah Gilbert, one of the project leaders. When that happens, noted the expert, it is possible to say that the vaccine works.
At the end of April, Sarah Gilbert said that the “best case scenario” would be that, in September 2020, “we have the capacity to manufacture large quantities of the vaccine”. However, the researcher admitted that this deadline could fail because there are two distinct parts of the problem: one is to check if the vaccine works (that is, if there are fewer contagions). The other part of the problem lies in the fact that it has the capacity to produce millions of doses by September, as is the goal.
At that time, however, the specialist spoke of the difficulties posed to this clinical test due to the fact that contagions and new hospital admissions are decreasing due to social confinement measures. This containment of the spread could be good for public health, but it would complicate scientific work in search of a vaccine that has been proven to be effective.
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