Following the breakthroughs in the race to deliver a coronavirus vaccine reported by Pfizer-BioNTech and then Moderna, the University of Oxford expects to release data on the efficacy of its own candidate in the coming weeks, with the latest trial results published in The Lancet suggesting it produces a strong immune response in older adults.
Developed jointly with global pharma giant AstraZeneca, who have enlisted manufacturing partners in different parts of the world, the ChAdOx1 nCov-2019 vaccine – it's a working title - is the one most likely to play a large role in any large or medium-scale vaccination effort in Bangladesh.
Phase 2 data published in The Lancet on Wednesday suggests one of the groups most vulnerable to serious illness and death from Covid-19 could “build immunity” on the ‘Oxford vaccine’, as it is more fondly known.
The vaccine has been shown to trigger a robust immune response in healthy adults aged 56-69 and over 70.
According to the researchers, the trial demonstrated similar immune responses across all three age groups – 18-55, 56-69, and 70 and over.
Upon closer scrutiny, the study of 560 healthy adults, including 240 over the age of 70, found, interestingly, that the vaccine is better tolerated in older people than in younger adults.
Volunteers 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.
In an interview Thursday with the BBC, Prof Andrew Pollard, one of the leaders of the Oxford Vaccine Group, said research was slowed by low infection rates over the summer, but the Phase III trials are now accumulating the data needed to report results as a renewed surge of the pandemic hits countries around the world.
“I think we’re getting close, and it’s definitely going to be before Christmas based on the progress,” he said.
Three vaccine candidates – from Pfizer-BioNTech, Moderna and Russia’s Sputnik- have already reported good preliminary data from phase three trials, each topping 90% in early efficacy readings. Public health experts have been willing to accept efficacy as low as 50%.
The Oxford data is from an earlier stage, which tests the safety of the vaccine and the body's response to it, but in the long run it's likely this vaccine could be easier to roll out because it doesn't need to be stored at very cold temperatures – as has been reported about the Pfizer and Moderna shots.
Maintaining the cold chain for coronavirus vaccines won’t be easy even in the richest of countries, especially when it comes to those that require ultracold temperatures of around minus 70 degrees Celsius (minus 94 F).
Earlier this month, Bangladesh entered into a deal with the Serum Institute of India (SII) to acquire 30 million doses of the potential vaccine being developed by AstraZeneca for Covid-19.
SII and Bangladesh’s own pharmaceutical giant, Beximco Pharma, signed a Memorandum of Understanding (MoU) for “priority delivery of the vaccine doses”.
Once the deal is activated following final approval of the vaccine, Beximco will purchase five million doses of the vaccine per month to distribute in Bangladesh – although under what type of scheme is still unclear.
SII will supply the vaccine at a price of around $4 to $5 per dose, a rate similar to what India pays. It partnered with AstraZeneca, the Gates Foundation and the Gavi vaccine alliance to produce over a billion doses of Covid-19 vaccine(s) for supply worldwide.
The latest data
As reported by the UK’s state news agency, the Press Association, Dr Maheshi Ramasamy, an investigator in the Oxford Vaccine Group and a 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.”
Researchers say their findings are promising as they show that older people are having a similar immune response to younger adults.
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 study also found that 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 after 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.