Oxford COVID-19 vaccine produces strong immune response

July 21, 2020 0 By FM

The results of the Phase I/II trial of the oxford vaccine ChAdOx1 nCoV-19 (AZD1222) have shown to induce strong immune responses with no early safety concerns, according to the findings published in the journal The Lancet.

The vaccine which was developed by the team of scientists at Oxford University’s Jenner Institute and Oxford Vaccine Group provoked a T cell response within 14 days of vaccination that could attack cells infected with the SARS-CoV-2 virus. The vaccine also generated an antibody response within 28 days. Antibodies are able to neutralise the virus so that it cannot infect cells when initially contracted by an individual hence protecting against the infection.

The Phase I/II trial of the vaccine has been 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, 2020, and May 21, 2020, 1077 volunteers, received the vaccine ChAdOx1 nCoV-19 or a placebo MenACWY vaccine.

Participants who received the vaccine had detectable neutralising antibodies, and the responses were stronger after a booster dose, with 100% of participants’ blood having neutralising activity against the coronavirus, noted the researchers.

“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,” said Professor Andrew Pollard, from the Oxford research group.

There were no serious adverse health events related to ChAdOx1 nCoV-19, and the immune responses observed following vaccination was in line with the previous animal studies, revealed the study.

“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,” noted the researchers.

However considering the effectiveness of the vaccine UK PM Borris Johnson pointed out that it is still uncertain how the vaccines would work immunising the virus upon infecting the individuals with the virus, which will require further studies. He added that “a widespread vaccination is likely to be, at the earliest, next year even if everything goes to plan.”

“We don’t know the level needed for protection, but we can maximise responses with a second dose,” noted Prof Pollard to the BBC.

The UK Phase I/II trial began in April testing the Oxford COVID-19 vaccine ChAdOx1 nCoV-19. The University of Oxford is working with the global biopharmaceutical company AstraZeneca for the further development, large-scale manufacture and potential distribution of the vaccine globally.

Oxford and AstraZeneca are collaborating with clinical partners around the world as part of a global clinical programme to trial the ChAdOx1 nCoV-19 (AZD1222) 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.

Once the late-stage clinical trials prove successful, Astra Zeneca has made commitments that the company would supply more than 2 billion doses of the vaccine as agreed with the UK, US, Europe’s Inclusive Vaccines Alliance (IVA), the Coalition for Epidemic Preparedness (CEPI), Gavi the Vaccine Alliance and Serum Institute of India.

Talking about the availability of the vaccine Dr. Adrian Hill, director of the Jenner Institute at Oxford University, said “There was a hope that if we had a vaccine quickly enough, we could put out the pandemic, however, noting the continuing surge of infections globally, I think its going to be very difficult to control this pandemic without a vaccine.”

“Even 2 billion doses may not be enough,” he said, underlining the importance of having multiple shots to combat the coronavirus.