A vaccine candidate developed at the University of Oxford has shown encouraging results in early human testing and appears to be “safe well-tolerated, and immunogenic”, according to a study published in The Lancet.
The COVID-19 vaccine (ChAdOx1) jointly developed by British-Swedish company AstraZeneca and the University of Oxford involves trials of 1,077 people that showed the injection led to them making antibodies and white blood cells (T-cells) that can fight coronavirus.
“Our preliminary findings show that the candidate ChAdOx1 nCoV-19 vaccine given as a single dose was safe and tolerated, despite a higher reactogenicity profile than the control vaccine, MenACWY,” the researchers, led by Pedro M Folegatti and Katiet Ewer, wrote in the study.
Oxford’s Covid-19 vaccine produces a good immune response, reveals new study.
Teams at @VaccineTrials and @OxfordVacGroup have found there were no safety concerns, and the vaccine stimulated strong immune responses: https://t.co/krqRzXMh7B pic.twitter.com/Svd3MhCXWZ
— University of Oxford (@UniofOxford) July 20, 2020
“No serious adverse reactions to ChAdOx1 nCoV-19 occurred. The majority of adverse events reported were mild or moderate in severity, and all were self-limiting,” the study said. The clinical trials of a potential COVID-19 vaccine on humans began in April.
How does the vaccine work?
The Oxford vaccine — called ChAdOx1 nCoV-19 — is made from a harmless chimpanzee virus. The AZD1222 vaccine, based on a chimpanzee adenovirus called ChAdOx1, elicited antibody and T-cell immune responses.
It is genetically modified to code for the spike protein of the human SARS-CoV-2 virus. This means that when the adenovirus enters vaccinated people’s cells it also delivers the spike protein genetic code.
This causes these people’s cells to produce the spike protein, and helps teach the immune system to recognise the SARS-CoV-2 virus, study lead author Andrew Pollard said.
What are antibodies and T-cells?
Nearly all effective vaccines induce both an antibody and a T-cell response. Antibodies are small proteins made by the immune system that stick onto the surface of viruses. Neutralising antibodies can disable the coronavirus.
Whereas the T-cells, a type of white blood cell, help co-ordinate the immune system and are able to spot which of the body’s cells have been infected and destroy them.
The results so far are promising, but the study cannot show whether the vaccine can either prevent people from becoming ill or even lessen their symptoms of COVID-19. More than 10,000 people will take part in the next stage of the trials in the UK. However, the trial has also been expanded to other countries.