London: The Covid-19 vaccine developed by scientists at the Oxford University produces strong immune responses in both parts of the immune system, showed results of the Phase I/II trial published in The Lancet medical journal on Monday.
The vaccine provoked a T cell response within 14 days of vaccination -- white blood cells that can attack cells infected with the SARS-CoV-2 virus -- and an antibody response within 28 days -- antibodies are able to neutralise the virus so that it cannot infect cells when initially contracted.
The strongest immune response was observed in participants who received two doses of the vaccine. The results showed no early safety concerns.
During the study, participants who received the vaccine had detectable neutralising antibodies, which have been suggested by researchers as important for protection.
These responses were strongest after a booster dose, with 100 per cent of the participants' blood having neutralising activity against the coronavirus, showed the results.
The next step in studying the vaccine is to confirm that it can effectively protect against the SARS-CoV-2 infection.
"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," said Andrew Pollard, Chief Investigator of the Oxford Vaccine Trial at the Oxford University and co-author of the study..
"The immune responses observed following the 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," Pollard said.
"We saw the strongest immune response in the 10 participants who received two doses of the vaccine, indicating that this might be a good strategy for vaccination," Pollard added.
A UK Phase I/II trial began in April for testing the Oxford coronavirus vaccine ChAdOx1 nCoV-19.
The team started working to develop a vaccine against the global threat that is coronavirus in January 2020.
During the Phase I/II trial, the vaccine was evaluated in more than 1,000 healthy adult volunteers aged between 18 and 55 years in a randomised controlled trial.
A subset of these volunteers --10 people -- received two doses of the vaccine.
Between April 23 and May 21, a total of 1,077 volunteers, received the vaccine ChAdOx1 nCoV-19 or a placebo MenACWY vaccine.
There were no serious adverse health events related to ChAdOx1 nCoV-19.
"These encouraging results support further evaluation of this candidate vaccine in our ongoing large scale Phase III programme, that is still needed to assess the ability of the vaccine to protect people from COVID-19," said Sarah Gilbert, Professor of Vaccinology at the University of Oxford's Jenner Institute and co-author of the study.
The University of Oxford is working with the UK-based global biopharmaceutical company AstraZeneca for further development, large-scale manufacture and potential distribution of the Covid-19 vaccine, with plans for clinical development and production of the Oxford vaccine progressing globally.
"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," said Mene Pangalos, Executive Vice President of BioPharmaceuticals Research and Development at AstraZeneca.
Oxford and AstraZeneca are collaborating with clinical partners around the world as part of a global clinical programme to trial the Oxford vaccine.
The global programme is made up of a Phase III trial in the US enrolling 30,000 patients, a paediatric study, as well as Phase III trials in low-to-middle income countries including Brazil and South Africa which are already underway.
The Serum Institute of India (SII) will soon apply to the Indian regulator for the licensure trials of the AstraZeneca-Oxford Covid vaccine.
Commenting on the AstraZeneca-Oxford vaccine's results, Adar Poonawalla, CEO, Serum Institute of India, said, "The trials have shown promising results and we are extremely happy about it. We will be applying for the licensure trials to the Indian regulator in a week's time. As soon as they grant us permission, we will begin with trials for the vaccine in India. In addition, we will soon start manufacturing the vaccine in large volumes."
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