Moderna vaccine's effectiveness bodes well for Oxford/AstraZeneca jab

By Nicola Davis and Jessica Elgot

Hopes are rising for the Covid jab being developed by Oxford University, after Moderna became the second company to reveal impressive results from its vaccine trials.

Interim results from phase 3 clinical trials of the Covid vaccine from US company Moderna has revealed it to be almost 95% effective at preventing the disease. The news followed an announcement last week from Germany-based Pfizer and BioNTech that their vaccine was more than 90% effective.

While the UK has secured 40m doses of Pfizer’s vaccine, and 5m of Moderna’s, it has by far the most riding on the jab being developed by Oxford University and AstraZeneca – of which it has reserved 100m doses.

Although the Oxford vaccine uses a different technology from the Moderna jab, the two vaccines both rely on stimulating cells to produce a specific protein, which in turn triggers an immune response – meaning Moderna’s results bode well for Oxford.

A source at the Department of Health and Social Care said the results from the Oxford vaccine trials were “imminent” and that it could be one of the first to be rolled out.

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Both the Moderna and Pfizer/BioNTech vaccines are based on introducing genetic material, known as mRNA, into the body. This carries instructions for making the coronavirus’s spike protein. The vaccine causes protein-making machinery within the human cells to churn out this spike protein, triggering the body’s immune response.

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The latest results will be exciting for researchers at Imperial College London, who are also developing a vaccine based on mRNA. But it also bodes well for vaccines in development that take a different approach yet are still focused on spike proteins. This includes Oxford’s, which uses a harmless chimp cold virus to deliver genetic information from the coronavirus to human cells to trigger the production of the spike protein.

“The fact that a further vaccine [is] directed at inducing immune responses against the S-protein [spike protein] is promising for all other vaccine candidates that have taken this approach, be it vectored or mRNA or inactivated vaccines,” said Prof Beate Kampmann, the director of the vaccine centre at the London School of Hygiene & Tropical Medicine.

Prof Andrew Pollard, director of the Oxford Vaccine Group, agreed. “The positive results from the other developers means it is likely that there will be multiple vaccines on target, which is great news for the world,” he said.

Pollard told the Guardian that the Oxford/AstraZeneca team expect to have findings from their phase 3 clinical trial within a matter of weeks.

Should that be the case, and the team also release their full safety data, some have suggested the vaccine could gain regulatory approval about the same time or before the Pfizer/BioNTech vaccine. The latter is only expected to finish gathering two months of safety data – the amount required by the US FDA for potential emergency use authorisation – by the third week of November.

But experts warned only so much can be inferred from the findings of other teams. “The Oxford vaccine uses a very different technology to the Pfizer/BioNTech or Moderna vaccines and so we don’t yet know if it will induce the right quality of immune response,” said Prof Eleanor Riley of the University of Edinburgh.

She noted that the Oxford/AstraZeneca vaccine takes a similar approach to the “Sputnik V vaccine” from Russia. Interim results, which have not yet been peer reviewed or published, suggested the Sputnik V vaccine is 92% effective at preventing Covid.

However, those results have been criticised by some experts who noted they are based on just 20 cases of Covid-19 among participants, a figure they said is too small to have drawn conclusions from.

While time will tell how effective the different vaccines truly are, it seems likely there will be a hamper of promising results by Christmas, with countries already lining up to secure doses.

At present, the UK has secured access to seven potential Covid vaccines across four different approaches, including 100m doses of the Oxford/AstraZeneca jab and 30m doses of a vaccine from Janssen Pharmaceutical Company, which is based on a similar approach to the Oxford/AstraZeneca vaccine and has just begun its phase 3 clinical trials.