By Alishah Khan, Edited by Kathleen Navas and Sami Morse
In April, an Oxford University research group and AstraZeneca, a Swedish company, launched development of a potential COVID-19 vaccine. The AstraZeneca-Oxford vaccine (called ChADOx1), is a live attenuated vaccine that uses chimpanzee adenovirus as a delivery system, meaning it uses adenovirus (a common cold virus with the SARS-CoV-2 spike protein) as a way to promote host antibodies that will help fight against SARS-CoV-2 infection. AstraZeneca chose to use adenovirus because it is well-studied as a viral vector--a virus that can carry genes from the pathogen of interest, which would be coronavirus.
After clearing preclinical trials, the virus went through phase 1 & 2 clinical trials without issue; the vaccine was tested on adults aged 18-55 with 2 doses over 28 days, and scientists did not record any severe side effects and found that the virus was immunogenic. Following these results, phase 2 & 3 trials began in England and India, with phase 3 trials commencing in South Africa, Brazil, and the US. The vaccine is already in mass production, with millions of doses produced. Many countries, such as India and several countries within the European Union, have agreed for millions of doses to be delivered.
On September 6, in the middle of the phase 3 trial, the AstraZeneca-Oxford vaccine made international news after one trial participant developed what was originally thought to be a serious side effect to the vaccine--an inflamed spinal cord. However, according to CNN, the participant was later found to have a “rare neurological condition” unassociated with the vaccine. It is worth noting that when vaccines are tested on such a wide scale, there are significant chances of people experiencing adverse effects unrelated to the vaccine itself. Adverse effects confirmed to be associated with the vaccine include fever, headaches, and muscle aches in 60% of patients. As of October 2020, clinical trials have resumed, and AstraZeneca/Oxford remain well on their way to developing a viable vaccine.
Results from ongoing research and the current understanding of COVID-19 are constantly evolving. This post contains information that was last updated on October 27, 2020.