Oxford COVID-19 Vaccine Produces Strong Dual Immune Response in 90% of People After One Dose

The University of Oxford (Oxford, UK) has published results of the Phase 1/2 trial of its COVID-19 vaccine candidate that indicate no early safety concerns and strong responses induced in both parts of the immune system.

The randomized, controlled Phase I/II trial that began in April for testing Oxford’s coronavirus vaccine ChAdOx1 nCoV-19 evaluated more than 1,000 healthy adult volunteers aged between 18 and 55 years. A subset of these volunteers (10 people) received two doses of the vaccine. Between April 23, 2020 and May 21, 2020, 1077 volunteers, received the vaccine ChAdOx1 nCoV-19 or a placebo MenACWY vaccine. Oxford’s COVID-19 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 neutralize the virus so that it cannot infect cells when initially contracted).


During the study participants who received the vaccine had detectable neutralizing antibodies, which have been suggested by researchers as important for protection, and these responses were strongest after a booster dose, with 100% of participants blood having neutralizing activity against the coronavirus. The next step in studying the vaccine is to confirm that it can effectively protect against SARS-CoV-2 infection. The University of Oxford is working with AstraZeneca (Cambridgeshire, England) for the 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.

“The Phase 1/2 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 program to confirm this in humans,” said Professor Andrew Pollard, Chief investigator of the Oxford Vaccine Trial at Oxford University and co-author of the study. “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.”

“We are encouraged by the Phase 1/2 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,” said Mene Pangalos, Executive Vice President of BioPharmaceuticals Research and Development at AstraZeneca.

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