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London (AFP)
The head of British drug maker AstraZeneca said Thursday that more research is needed on its Covid-19 vaccine after questions were raised about the protection it offers, but further testing is unlikely to affect regulatory approval in Europe.
AstraZeneca and its partner, the University of Oxford, announced Monday that they were seeking regulatory approval for the vaccine after it showed an average effectiveness of 70 percent.
That rate jumped to 90 percent when a starting half dose and then a full dose were administered, similar to rival vaccines in development by Pfizer / BioNTech and Moderna.
But American scientists have said that the highest rate of effectiveness occurred during testing in people 55 and younger, and was discovered by accident during clinical trials.
The director of the Oxford Vaccine Group, Andrew Pollard, said this week that more evidence will be available next month, but that the result remains “very significant.”
“Now that we’ve found what looks like better efficacy, we have to validate this, so we need to do an additional study,” AstraZeneca chief Soriot told Bloomberg.
He said he hoped it would be another “international study, but this one could be faster because we know the efficacy is high, so we need fewer patients.”
The additional trial is not likely to delay regulatory approval in Britain and the European Union, AstraZeneca CEO Pascal Soriot said.
There are high hopes for the AstraZeneca / Oxford vaccine, which Pollard has hailed as a “vaccine for the world,” given that it could be cheaper to make and easier to store and distribute.
It can be stored, transported and handled under normal refrigeration conditions of between two and eight degrees Celsius (36-46 Fahrenheit) for at least six months.
The Pfizer / BioNTech offering calls for temperatures of -70 ° C, which increases costs and potentially makes it out of reach for low- and middle-income countries.
AstraZeneca / Oxford is also committed to providing its vaccine to the developing world on a non-profit basis.
– Wait and see –
Helen Fletcher, a professor of immunology at the London School of Hygiene and Tropical Medicine, said the available safety data on the vaccine had been “very strong.”
But he said it was important to wait for the full data set.
“It is possible that a lower starting dose of vaccine could result in greater vaccine efficacy … More is not necessarily better when it comes to vaccines and immunotherapies,” he added.
“It is also possible that a strong immune response to the first vaccine can effectively block an immune response to the second injection of the same virus.”
Fletcher’s colleague, professor of pharmacoepidemiology Stephen Evans, said that speculation about the age distribution in the trials “was not helpful to anyone.”
“We have good reason to trust that regulation in this high-profile area will be done with the same or more care for these vaccines than for any others in the past,” he added.
Gillies O’Bryan-Tear from the UK College of Pharmaceutical Medicine said that “the eventual efficacy rate may change” but “the validity of the results from the low dose / high dose group is unlikely to be questioned “.
“Even if (regulators) decide to ignore the results of the low dose / high dose group, the study of the high dose / high dose patients will still be very significant, but I think it is unlikely,” he added.
© 2020 AFP
