Oxford University's Coronavirus Vaccine Shows Very Encouraging Results in Tests on Monkeys

The University of Oxford’s (Oxford, UK) candidate for a coronavirus vaccine has shown promising signs after being tested on a small number of monkeys in a new study.

Oxford University’s ChAdOx1 nCoV-19 vaccine 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 Oxford researchers gave six rhesus macaques half the dose of the ChAdOx1 nCoV-19 vaccine which is presently being tested in humans. In the case of mice, some of them developed antibodies to the virus within 14 days of being vaccinated, while all the animals provided evidence of antibodies within 28 days. The study found that a single vaccination dose was also effective in preventing damage to the lungs and significantly reduced viral loads in the lower respiratory system, indicating that the vaccine arrests virus replication in the lower respiratory tract.

“We observed a significantly reduced viral load in bronchoalveolar lavage fluid and respiratory tract tissue of vaccinated animals challenged with SARS-CoV-2 compared with control animals, and no pneumonia was observed in vaccinated rhesus macaques. “Importantly, no evidence of immune-enhanced disease following viral challenge in vaccinated animals was observed,” wrote the authors.

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