Oxford University coronavirus vaccine prompts immune response in early test

The first set of results on the trial of a Covid-19 vaccine developed by the Oxford University has shown that the vaccine is safe and induces an immune reaction at least for nearly two months.

Published in the Lancet medical journal on Monday, the preliminary data from the trial on 1,077 healthy adults demonstrate the vaccine’s short term and long term protective responses up to 56 days. The responses may be greater with a second dose.

Now it will have to undergo a bigger trial with larger participants, whose success will determine when the vaccine would be commercialised.

One of the partners in the project is Pune-based vaccine maker Serum Institute of India that would manufacture the vaccine commercially if the trials are successful.

“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 the trials for the vaccine in India. In addition, we will soon start manufacturing the vaccine in large volumes," Adar Poonawalla, CEO of Serum Institute of India said in a statement.

In an interview on Sunday, Poonawalla said he hoped that the vaccine would be available by the end of 2020.

Pharmaceutical major AstraZzeneca is also a partner in the Oxford vaccine project.

Compared to the control group (given a meningitis vaccine), the SARS-CoV-2 vaccine caused minor side effects more frequently, but some of these could be reduced by taking paracetamol. There were no serious adverse events from the vaccine.

Based on their results, the researchers said, further clinical studies, including in older adults, should be done with this vaccine. The current results focus on the immune response measured in the laboratory, and further testing is needed to confirm whether the vaccine effectively protects against infection.

Phase 2 and 3 trials of the vaccine are going on in the UK, Brazil and South Africa.

“The new vaccine is a chimpanzee adenovirus viral vector (ChAdOx1) vaccine that expresses the SARS-CoV-2 spike protein. It uses a common cold virus (adenovirus) that infects chimpanzees,” said study lead author Dr Andrew Pollard, University of Oxford.

“It has been weakened so that it can’t cause any disease in humans, and 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 delivers the spike protein genetic code. This causes the human cells to produce the spike protein, and helps teach the immune system to recognise the SARS-CoV-2 virus.”

Interestingly a second adenovirus based vaccine developed by Chinese researchers has also been found safe and induced an immune response in a phase-2 trial involving 500 people. Phase 3 trials are needed to confirm whether the vaccine candidate effectively protects against SARS-CoV-2 infection, according to another study published in the same issue of the Lancet.

The Chinese scientists pointed out that since no participants were exposed to SARS-CoV-2 virus after vaccination, it was not possible to determine whether the vaccine candidate effectively protects against SARS-CoV-2 infection.

“The phase 2 trial adds further evidence on safety and immunogenicity in a large population than the phase 1 trial. This is an important step in evaluating this early-stage experimental vaccine and phase 3 trials are now underway,” said Dr Feng-Cai Zhu, Jiangsu Provincial Center for Disease Control and Prevention, China.