The story so far: On April 23, Oxford University initiated a phase-1 human clinical trial of its vaccine — ChAdOx1 nCoV-19 — against the novel coronavirus, SARS-CoV-2. A single dose of the candidate vaccine will be administered to 1,112 healthy volunteers to study the safety, ability to produce immune response and efficacy of the vaccine. Oxford University is optimistic of a positive outcome of the candidate vaccine and has planned to get millions of doses of the vaccine before the end of the year even as results of the final phase of the trial (phase-3) are awaited. The vaccine candidate was developed by the University’s Jenner Institute which began trials in humans on April 23 jointly with the University’s Oxford Vaccine Group.
How was the vaccine being tested constructed?
The vaccine, ChAdOx1 nCoV-19, uses the common cold virus (adenovirus) that causes infections in chimpanzees. The adenovirus has been genetically altered so that it does not grow once injected. The construct carries the genetic material of the novel coronavirus that makes the spike protein. The spike protein is found on the surface of the virus and plays a crucial role in binding to specific human receptors found on cell surfaces and entering the cells.
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By introducing the genetic material of the spike protein, the candidate vaccine will help the body recognise it and make antibodies against the spike protein. The antibodies produced will help mount an immune response and prevent the virus from entering the human cells and causing an infection.
Oxford University has used vaccines made from the adenovirus construct to over 320 people and has found it to be safe and well tolerated. It does cause transient side effects such as a fever, headache or a sore arm but is otherwise safe.
Has it been tested on animals?
The adenovirus construct has been used by Oxford University researchers to test safety for both the 2002 Severe Acute Respiratory Sy