University of Oxford's Covid-19 vaccine shows immune response
A Covid-19 vaccine being trialled by the University of Oxford has found to be safe and is able to produce strong immune responses in patients, according to results from a latest study.
Earlier this year, the University of Oxford signed a partnership with pharma company AstraZeneca to test its Covid-19 vaccine candidate (AZD1222). AstraZeneca’s candidate is an adenovirus vaccine vector which was selected due to its ability to generate strong immune responses from a single dose. The vaccine candidate is also not a replicating virus, meaning it cannot cause an ongoing infection and making it safer to give to children, the elderly, and those with pre-existing conditions.
Now, results from a Phase I/II study of 1,077 participants show that a single dose of AZD1222 resulted in a four-fold increase in antibodies one month after injection. Two doses of the vaccine were also given to 10 patients, with 100% of these participants showing neutralising activity against the coronavirus.
“The Phase I/II data for our coronavirus vaccine shows that the vaccine did not lead to any unexpected reactions and had a similar safety profile to previous vaccines of this type. The immune responses observed following vaccination are in line with what previous animal studies have shown are associated with protection against the SARS-CoV-2 virus, although we must continue with our rigorous clinical trial programme to confirm this in humans,” lead study author professor Andrew Pollard said.
The vaccine was shown to provoke a T-cell response within two weeks and an antibody response within four weeks. T-cells and antibodies are vital in helping the body fight off viruses, with the former attacking infected cells and the latter helping the body neutralise the virus so cells cannot be infected when initially contracted.
Though the results are positive, the researchers still need to confirm whether AZD1222 can effectively protect against SARS-CoV-2 infection.
While there were no serious adverse effects associated with the vaccine, side effects did include headaches, fever and muscle aches in a range of patients.
Discussing the limitations of the study, the researchers stated that their findings are largely based off of a majority of young and healthy volunteers, most of whom were white. The volunteers of this study will be followed up for at least one year, with the results being published when available.
The vaccine must now be tested as part of a number of Phase III trials, as well as a paediatric trial to assess how it performs across a range of populations.
The University of Oxford and AstraZeneca are now working with a range of clinical partners across the globe to test the vaccine in a number of Phase III trials. These include a study in the US involving 30,000 patients, a paediatric study, and Phase III trials in countries including Brazil and South Africa which are already underway.
“We are encouraged by the Phase I/II interim data showing AZD1222 was capable of generating a rapid antibody and T-cell response against SARS-CoV-2. While there is more work to be done, today’s data increases our confidence that the vaccine will work and allows us to continue our plans to manufacture the vaccine at scale for broad and equitable access around the world,” says Mene Pangalos, executive vice president of BioPharmaceuticals Research and Development at AstraZeneca.
Responding to the study results, chief executive of the Association of British Pharmaceutical Industry (ABPI) Dr Richard Torbett, said: “All over the world, pharmaceutical companies are working in partnership in the search for an effective Covid-19 vaccine and today’s announcement of progress in the UK is extremely positive.
Developing a vaccine is an incredibly difficult challenge; the fact that there are multiple candidates in development is hopefully a sign that the hard work will ultimately pay off.
But we must be patient. Proving that a vaccine is safe and effective is a long process and we could still be many months away.”