Oxford’s COVID-19 Vaccine Begins Testing in Human Volunteers

The University of Oxford’s (Oxford, UK) candidate for a coronavirus vaccine has entered the human trial stage with researchers commencing testing of the COVID-19 vaccine in human volunteers.

The new vaccine called ChAdOx1 nCoV-19 is based on an adenovirus vaccine vector and the SARS-CoV-2 spike protein, and has been produced in Oxford. It is made from a virus (ChAdOx1), which is a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees, that has been genetically changed so that it is impossible for it to grow in humans. Genetic material has been added to the ChAdOx1 construct, that is used to make proteins from the COVID-19 virus (SARS-CoV-2) called Spike glycoprotein (S). This protein is usually found on the surface of SARS-CoV-2 and plays an essential role in the infection pathway of the SARS-CoV-2 virus. The SARS-CoV-2 coronavirus uses its spike protein to bind to ACE2 receptors on human cells to gain entry to the cells and cause an infection. By vaccinating with ChAdOx1 nCoV-19, the researchers are hoping to make the body recognize and develop an immune response to the Spike protein that will help stop the SARS-CoV-2 virus from entering human cells and therefore, prevent infection.

In March, the researchers began screening healthy volunteers (aged 18-55) to test the ChAdOx1 nCoV-19 vaccine against COVID-19 in healthy volunteers. The study aims to assess whether healthy people can be protected from COVID-19 with the vaccine and also provide valuable information on safety aspects as well as its ability to generate good immune responses against the virus. The participants will be randomly allocated to receive either the ChAdOx1 nCoV-19 vaccine or a licensed vaccine (MenACWY) that will be used as a ‘control’ for comparison. To assess whether the ChAdOx1 nCoV-19 vaccine works to protect from COVID-19, the researchers will compare the number of infections in the control group with the number of infections in the vaccinated group. If the levels of virus transmission in the community remain high, the researchers expect to get enough data in a couple of months to confirm that the vaccine works, although this could take up to six months if transmission levels drop.

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