Oxford COVID-19 Vaccine Could Offer ‘Double Protection’ Against Novel Coronavirus

The University of Oxford’s (Oxford, UK) COVID-19 vaccine has generated an immune response against the disease in Phase I human trials and could offer a "double defense" against the novel coronavirus.

The 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.

The latest findings of Oxford’s COVID-19 vaccine are based on initial results from a Phase I clinical trial which began in April in which doses of the vaccine were given to 500 volunteers. The study aimed 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. Now, a report by The Telegraph has said that Oxford scientists have found both antibodies and "killer T-cells" in blood samples taken from the group of volunteers who were administered the vaccine. The results are highly encouraging amidst reports of various studies which have found that antibodies can disappear in months, while T-cells can remain in circulation for years.

However, a senior source of The Telegraph has cautioned that although the results were "extremely promising", they did not yet prove that the Oxford vaccine could deliver long-lasting immunity against COVID-19. "I can tell you that we now know the Oxford vaccine covers both bases-it produces both a T-cell and an antibody response. It's the combination of these two that will hopefully keep people safe. So far, so good. It's an important moment. But we still have a long way to go."

Yet another source who is close to the Oxford team termed the presence of both antibodies and T-cells as a "double defense" against COVID-19. The full findings of the Phase I clinical trial of Oxford’s COVID-19 vaccine will be published in the Lancet medical journal on July 20.

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