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First trial results show UK coronavirus vaccine produces a strong immune response

Published: 20 July 2020

A new experimental vaccine for coronavirus induces strong immune responses in both parts of the immune system and causes few mild side effects, in promising results from a trial funded and supported by the NIHR.

The team of scientists at University of Oxford’s Jenner Institute and Oxford Vaccine Group, who are funded by the NIHR and UKRI, say they have taken the next step towards the discovery of a safe, effective and accessible vaccine against coronavirus. 

The results of the early trial, published in The Lancet, show that the ChAdOx1 nCoV-19 vaccine generated strong immune responses in both parts of the immune system, activating white blood cells that can attack cells infected with the SARS-CoV-2 virus, and antibodies that find and attack the virus when it's circulating in the blood or lymphatic system. 

The researchers also found that immune responses may be even greater after a second dose. Participants who received the vaccine had detectable neutralising antibodies up to day 56 of the ongoing trial. These responses were strongest after a second booster dose, with 100% of participants’ blood having neutralising activity against the coronavirus. Researchers have suggested that these antibodies are important for protection against the virus.

People who received the coronavirus vaccine were more likely to experience mild side effects such as headaches and fever than people in the control group (who received a meningitis vaccine), but some of these could be reduced by taking paracetamol. There were no serious side events from the vaccine.

Professor Andrew Pollard, Chief investigator of the Oxford Vaccine Trial at University of Oxford and co-author of the study, said: “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.” 

During the phase I/II randomised controlled trial, which launched in April, the vaccine has been evaluated in 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. 

Professor Sarah Gilbert, Professor of Vaccinology at the University of Oxford Jenner Institute and co-author of the study, said: “These encouraging results support further evaluation of this candidate vaccine in our ongoing large scale phase III programme, which is still needed to assess the ability of the vaccine to protect people from COVID-19.”

The phase I/II trial of the vaccine has been designated an urgent public health study by the Department of Health and Social Care, to expedite set up and delivery of the study in the health and care system, as has the phase II/III trial of the vaccine.

The University of Oxford is working with the UK-based global biopharmaceutical company AstraZeneca 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. 

Business Secretary Alok Sharma said: “Today’s results are extremely encouraging, taking us one step closer to finding a successful vaccine to protect millions in the UK and across the world. Backed by £84 million Government investment for the vaccine’s development and manufacture, the agility and speed with which the University of Oxford have been working is outstanding. I am very proud of what they have achieved so far.”

Kate Bingham, Chair of the UK's Vaccine Taskforce, said: “The UK is fortunate to have such outstanding academic innovators working alongside the highly experienced global team at AstraZeneca. This partnership is working at exceptional speed to demonstrate the safety and clinical effectiveness of the ChAdOx1 vaccine in protecting people against COVID-19 infection.”

Read the University of Oxford story

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