Oxford University’s coronavirus vaccine triggers a ‘robust’ response from the immune system and appears to work in older people, a study revealed today.
Scientists behind the project this morning published the results of an early trial of the jab, which found it created strong signs of immunity in 99 per cent of people.
The second-phase study included 560 people, most of whom were white and British, and showed that people across all age groups seemed to react equally well to the jab. It adds to data published in July suggesting it would work safely for under-55s.
It marks another breakthrough in the race to develop a vaccine to prevent Covid-19, after jabs made by Moderna and Pfizer and BioNTech were both revealed to be around 95 per cent effective within the past week.
Oxford’s results are from an earlier stage of testing so cannot estimate how well the vaccine protects against Covid, but are still a positive step. More detailed results are expected within weeks, the university said.
The research showed that people in all age groups developed antibodies – virus-destroying substances made by the immune system – within 28 days of their first dose of the vaccine, and these were boosted further after the second dose.
It showed that the vaccine caused more side effects than a fake jab but that these were ‘mild’ and more common in young people than older participants.
Within the first week after having the injection more than eight out of 10 under-55s said their arm hurt and and they later experienced tiredness, muscle aches or headaches.
Britain has pre-ordered 100million doses of Oxford’s jab, which is being made with pharmaceutical firm AstraZeneca, so if it works and can be manufactured fast enough it could be used to protect the majority of the UK’s population.
Data showing how well the vaccine actually protects against coronavirus are expected in the coming weeks, the team said.
Scientists today described the news as ‘promising’ and ‘positive’, adding that the UK’s order could be big enough to reach herd immunity if the vaccine comes good.
Although the early phases of Oxford’s trial have not tested the vaccine on many people in non-white groups or people with serious health conditions, a bigger study has recruited people from all over the world to check the jab works on everyone (Pictured: A woman in Brazil receives a dose of the vaccine)
British Prime Minister Boris Johnson is pictured during a visit to Oxford University’s Jenner Institute, where the vaccine was developed
Oxford published the results from tests of its vaccine, named ChAdOx1 nCov-2019, in UK medical journal The Lancet today.
Volunteers in the trial demonstrated similar immune responses across all three age groups – they had been split into 18-55, 56 to 69, and 70-plus.
Observations of the 560 adults – including 240 over the age of 70 – found the vaccine was actually better tolerated and caused fewer side effects in older people.
The news that the jab appears to be safe and effective for older people is a huge step forward for the project, because this is the group most at risk of severe Covid-19 and death.
Health officials in the UK have suggested that vaccines for younger adults and children are lower priority, and that vaccinating the over-50s and people with serious health conditions would cover the vast majority of people likely to die.
Professor Deborah Dunn-Walters, chair of the British Society for Immunology, described the announcement as ‘positive’.
She said: ‘While this is an ongoing study, the initial results are encouraging.
‘The vaccine appears to be well tolerated in all age groups, with older individuals reporting fewer side-effects.’
The Faculty of Pharmaceutical Medicine’s Dr Gillies O’Bryan-Tear explained: ‘The ageing of the immune system in older people can lead to lower efficacy of vaccines.
‘This is especially important as Covid has much higher lethality in older people.
‘One clue to this from the current study is that older people reacted less to the vaccine – fewer fevers, less injection site pain and swelling – but encouragingly, the immune responses in the older patients were indistinguishable from those in younger patients.
‘This suggests, but does not prove, that the protection against the illness will be similar in the elderly and the young.’
And Dr Michael Tildesley, a Warwick University epidemiologist who advises SAGE, said the vaccine could be a ‘game changer’.
He told BBC Breakfast the number of doses acquired by the Government could push the UK towards ‘that magic herd immunity’
Successfully protecting older people was the ‘really key thing’, he said.
Volunteers in the study were split into two groups and either received two doses of the real vaccine candidate or a placebo meningitis vaccine.
The placebo is given so scientists can be sure that any side effects people report are actually caused by the vaccine and not just the injection itself or psychological.
No serious health problems related to the vaccine were seen in any of the participants, the researchers said.
Dr Maheshi Ramasamy, investigator in the Oxford Vaccine Group and a consultant doctor, 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, but 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.’
Oxford’s vaccine is being produced by Cambridge-based pharmaceutical firm AstraZeneca
The vaccine is known as a recombinant viral vector vaccine and is made using a piece of the real coronavirus but not enough of it to cause illness.
In this case, scientists modified a cold virus found in monkeys to make it look like the coronavirus by attaching the ‘spike’ proteins found on the Covid virus to the outside.
This means that when the vaccine is injected, the spikes make the body think it is seeing the coronavirus and the immune system attacks it.
In the process it develops an understanding and memory of how to fight off any virus that has the same spikes on the outside, so if it encounters the coronavirus for real it should know immediately how to destroy it before it can cause Covid-19.
Oxford’s announcement comes after late-stage clinical trial results were reported by pharma firms Moderna and Pfizer and BioNTech this week.
Pfizer and BioNTech yesterday said the final results of their clinical trial suggested their vaccine was 95 per cent effective, just days after Moderna claimed its own jab showed efficacy of 94.5 per cent.
The UK is now in the process of getting these through regulatory approval and will buy millions of doses if they’re approved.
Up to five million people could be vaccinated with Pfizer’s jab before the end of the year if the process goes smoothly.
Oxford’s vaccine is expected to be considerably cheaper than either of those, has been ordered in huge quantities and will be easier to store and deliver.
While Moderna’s is expected to cost between £24 and £28 per dose, and Pfizer’s around £15 per dose, Oxford’s could cost just £2.23.
Manufacturer AstraZeneca said it would produce the first batch of vaccines ‘at cost’, meaning it won’t profit from them, although it could up the price in the future.
Storage and transport of Oxford’s vaccine is likely to be cheaper, too, with previous versions of the same technology suitable for storing at room temperatures.
Pfizer and Moderna both say their vaccines must be frozen during transport and then kept cold up until the point they’re used in a clinic.
Pfizer’s will be particularly challenging because it has to be kept at an ultra-cold -70°C (-94°F) throughout the supply chain, which requires specialist freezers.
Moderna’s is less difficult because it only needs to be frozen during transport, at a temperature that normal freezers are capable of reaching, and can then be kept in a fridge.
Oxford’s can be kept stable in temperatures between 2°C and 8°C, meanwhile, meaning it could be kept in a standard fridge at all times so no new equipment would need to be bought.
Today’s Lancet study also found the vaccine, being developed with AstraZeneca, was less likely to cause local reactions at the injection site and symptoms on the day of vaccination in older adults than in the younger group.
Adverse reactions were mild – injection-site pain and tenderness, fatigue, headache, feverishness and muscle pain – but more common than seen with the control vaccine.
Thirteen serious adverse events occurred in the six months since the first dose was given, none of which were related to either study vaccine.
The authors note some limitations to their study, including that the participants in the oldest age group had an average age of 73-74 and few underlying health conditions, so they may not be representative of the general older population, including those living in residential care settings or aged over 80.
Phase three trials of the vaccine are ongoing, with early efficacy readings possible in the coming weeks.
UK authorities have placed orders for 100million doses of the vaccine – enough to vaccinate most of the population – should it receive regulatory approval.
The Oxford findings come after Pfizer and BioNTech announced that their vaccine candidate has shown 95 per cent efficacy, with a 94 per cent effectiveness in those aged 65 and over.
Forty million doses of that vaccine have been bought by the UK, with rollout potentially starting in early December if the jab is given the green light by regulators.
Earlier in the week US biotech firm Moderna released data suggesting its vaccine is almost almost 95 per cent effective.