The UK’s coronavirus vaccine has shown to produce a strong immune response in older adults – suggesting one of the groups most vulnerable to serious illness and death from Covid-19 could build immunity.

Early stage results from a study of the University of Oxford Covid-19 vaccine, published in the medical journal The Lancet, showed the jab triggered a robust immune response in healthy adults aged 56-69 and people over 70.

The phase two research demonstrated similar immune responses from the vaccine – which is being developed with AstraZeneca – across all three age groups (18-55, 56-69, and 70 and over). This included antibodies and T-cells.

However, researchers said it was not yet clear if older people will need more booster jabs to maintain this good immune response, compared to younger people. 

The study of 560 healthy adults – including 240 over the age of 70 – also found the vaccine is better tolerated in older people compared with younger adults.

Not only did those in older age groups experience fewer side-effects in the aftermath of receiving the jab, such as headaches, fatigue and nausea, but they were milder. 

But scientists involved in the trial said they did not think this correlated to a weaker immune response, as it does with some vaccines. 

Volunteers in the trial received two doses of the vaccine candidate, or a placebo meningitis vaccine.

No serious adverse health events related to the vaccine were seen in the participants.

The results are consistent with phase one data reported for healthy adults aged 18-55 earlier this year.

Phase three trials are ongoing to confirm these results and the University of Oxford is expected to release data on the effectiveness of its coronavirus vaccine before Christmas. 

UK authorities have placed orders for 100 million doses of the vaccine – enough to vaccinate most of the population – should it receive regulatory approval.

Dr Maheshi Ramasamy, 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, 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.”

Study lead author Professor Andrew Pollard, from the University of Oxford, said: “Immune responses from vaccines are often lessened in older adults because the immune system gradually deteriorates with age, which also leaves older adults more susceptible to infections.

“As a result, it is crucial that Covid-19 vaccines are tested in this group who are also a priority group for immunisation.”

Researchers say their findings are promising as they show that the older people are showing a similar immune response to younger adults.

Dr Ramasamy added: “The robust antibody and T-cell responses seen in older people in our study are encouraging.

“The populations at greatest risk of serious Covid-19 disease include people with existing health conditions and older adults.

“We hope that this means our vaccine will help to protect some of the most vulnerable people in society, but further research will be needed before we can be sure.”

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.

However, researchers said this would be addressed in phase three of the study.

It comes amid a welter of positive news about the vaccine.

The coronavirus vaccine from Pfizer – which is due to arrive in the UK before the end of the year – is 95% effective and works in older people, according to new data from the firm.

The UK has secured 40 million doses in total of the vaccine, with 10 million due in the country by the end of the year if the vaccine is approved.

People will need two doses, meaning not enough vaccine has been secured for the entire UK population.

Another jab, from US firm Moderna, was shown this week in early data to be almost 95% effective.

The UK has ordered five million doses of that jab, and also awaits the results of the Oxford University and AstraZeneca vaccine study.

Changes to the Human Medicine Regulations announced in October will allow the Medicines and Healthcare products Regulatory Agency (MHRA) to authorise temporary supply of vaccines, if one becomes available before 2021.

This means that if a vaccine is found to meet the safety, quality and effectiveness standards by the MHRA then vaccinations can begin without needing to wait for the European Medicines Agency.

The health secretary Matt Hancock has said the NHS will be ready by December 1 to roll out vaccines and that the MHRA could approve a jab “within days” of a licence application.

Pfizer and BioNTech expect to be able to produce up to 50 million vaccine doses globally in 2020 and up to 1.3 billion in 2021.

The vaccine needs to be kept at an ultra-low temperature, between minus 70C and minus 80C, until a few days before use when it can be transferred to a standard medical fridge.

If it is approved for use in the UK it will need to be stored in regional hubs – including wholesalers and hospitals – before being shipped to GP surgeries and vaccination clinics.

The Oxford vaccine, on the other hand, can be stored at normal fridge temperature, Professor Andrew Pollard said, with GP surgeries already supplied with vaccine fridges.