COVID-19: Oxford vaccine produces strong immune response in older adults, early results show

·5-min read

The COVID-19 vaccine developed by Oxford University produces a strong immune response in older adults, data from early trials has shown.

The phase one and phase two results suggest that one of the groups most at risk of death or serious illness from COVID-19 may be able to build immunity, according to data published in The Lancet medical journal.

It comes a day after Pfizer announced its coronavirus vaccine was 94% effective among adults over 65 in its final efficacy results, and that it would be seeking authorisation over the next few days.

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Responding to the news, Health Secretary Matt Hancock tweeted: "There is still much work to be done, but this is a really encouraging set of findings from the @UniofOxford and @AstraZeneca vaccine."

According to the authors of the Oxford vaccine findings, "volunteers in the trial demonstrate similar neutralising antibody titres, and T cell responses across all three age groups (18-55, 56-79, and 70+)".

Around 560 healthy adult volunteers took part in the phase two trials, where they were given two doses of the vaccine candidate, or a placebo.

No adverse health problems were reported during the trials, the report adds.

The University of Oxford says that across most vaccines, older adults tend not to be as well protected as younger adults, with antibodies induced by a vaccine often showing a lower protective capacity.

Dr Maheshi Ramasamy, an investigator at the Oxford Vaccine Group and consultant physician, said: "Older adults are a priority group for COVID-19 vaccination, because they are at increased risk of severe disease, but we know that they tend to have poorer vaccine responses.

"We were pleased to see that our vaccine was not only well tolerated in older adults; it also stimulated similar immune responses to those seen in younger volunteers. The next step will be to see if this translates into protection from the disease itself."

Phase three trials of the Oxford/AstraZeneca jab, which will determine the vaccine's efficacy, are still ongoing, with results expected over the coming weeks.

Professor Andrew Pollard, the head of Oxford's vaccine trial team, said the team were "delighted" with the latest results showing that 99% of people produce a good antibody response following vaccination, including the elderly.

Studies suggest the Oxford jab would not need to be kept at temperatures as low as those made by Pfizer and Moderna.

Prof Pollard said he is optimistic that data on whether the Oxford vaccine prevents COVID-19 will be ready before Christmas.

"We are not in a rush. It is not a competition with other developers," he said. "We are trying to make sure we have high quality data. As for the timing? Results will be presented when they are ready."

He said the final timing of a vaccine roll-out will depend, in part, on how quickly the regulatory authorities can complete their assessment of all the vaccines' safety and efficacy data.

"It's possible things line up so there is not very much difference in the timing between the vaccines," he added.

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The UK government has ordered more than 100 million doses of the Oxford vaccine and will hope the final results prove similarly promising to those of Pfizer and US firm Moderna, which have reported overall efficacies of 95% and 94.5% respectively.

Dr Michael Tildesley, who sits on a SAGE sub-group, said the vaccine is "going to be hopefully one of the key game changers" because the number of doses acquired by the government will allow the UK to "hopefully reach that magic herd immunity".

Dr Tildesley, a member of the Scientific Pandemic Influenza Modelling (SPI-M) group, told BBC Breakfast the vaccine's strong immune response in older adults is "the really key thing" for preventing deaths.

One Oxford vaccine trial volunteer said she did not experience any adverse side effects, adding: "I was so surprised."

Sarah Hurst, 47, from Oxfordshire, said she signed up because she "wanted a vaccine as quickly as possible so we can live our lives again".

She said she hoped the jab would prove to be as effective as the other two.

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Analysis: Medical textbooks being rewritten before our eyes

By Thomas Moore, science correspondent

For decades it's been a "rule" of vaccine science that the older the person, the less well their immune system will respond to a jab.

It's called immunosenescence. Another downside of aging.

But perhaps the medical textbooks are being rewritten before our eyes.

The scramble to develop an effective vaccine against COVID-19 has accelerated the development of jabs based on new genetic technologies.

And they're proving to be much better at generating an immune response in older people than had been expected.

The results of a newly published clinical trial of the Oxford Vaccine are encouraging. It triggers an immune response that's just as good in those over 55 as in younger people.

That's only based on an analysis of antibody and T-cell levels in blood samples though.

It's not real-world protection against infection.

That's the ultimate test for any vaccine and we won't get that information until the Oxford/AstraZeneca team release details of the final stage, phase three trials, which could come any day now.

Pfizer/BioNTech have already shown their vaccine is more than 94% effective in preventing COVID-19 in the elderly. That laid down a marker for the other vaccines.

Hopefully they match it. We will need every jab going if we are to protect those most vulnerable to serious disease - and stand a chance of returning life to normal by next autumn.