- On Tuesday, AstraZeneca and the Oxford University published their phase 3 trial data in a peer-reviewed journal
- According to the results, the Oxford vaccine is 70% effective at preventing COVID-19 in healthy individuals
- Its counterparts, Pfizer/BioNTech and Moderna have both reported a vaccine efficacy of over 90%.
AstraZeneca is the first vaccine manufacturer to have its clinical trial data published in a scientific journal. Thus, first to have peer-reviewed results.
AstraZeneca/Oxford Vaccine is Safe and Effective
The phase 3 trial included over 20,000 volunteers from across the United Kingdom (U.K), South Africa and Brazil. Half the participants received the vaccine while the other half became part of a control group and received a placebo. The vaccine is generally given in two doses, few weeks apart. However, due to a mishap a small group of volunteers ended up receiving half a dose as their first vaccine dose.
According to the study published in The Lancet, the vaccine showed an efficacy of 90% in those given a half and full dose. Whereas, in those who received two full doses, the vaccine efficacy was 62%. Researchers are unclear about the difference in results. Pooling of data revealed an overall vaccine efficacy of 70%.
Furthermore, only three participants out of the 23,745 participants developed an adverse reaction during the trial. Two of these participants were part of the vaccine group. However, researchers did not observe any hospitalizations or severe disease in the vaccinated group 3 weeks after the initial dose. Thus, confirming the vaccine to be safe.
Oxford vs Moderna vs Pfizer
Unlike Moderna and Pfizer, the Oxford vaccine is made using a chimpanzee adenovirus containing the SARS-CoV-2 spike protein. However, the viral protein is unable to cause infections in humans. Instead, it causes the immune system to produce antibodies against the foreign agent. Thus, eliciting an immune response. Antibodies then help fight off any future infections with the novel coronavirus.
Despite Pfizer and Moderna having a greater vaccine efficacy, the Oxford vaccine is comparatively safer, cheaper and easier to store and distribute. The team now plans to submit its data to various regulatory authorities across the world.
The Lancet (2020). DOI: 10.1016/S0140-6736(20)32661-1 , www.thelancet.com/journals/lan … (20)32661-1/fulltext