Top Coronavirus Vaccine Candidates – Most Promising Vaccine Candidates
The Lancet magazine published the results of the phase 2 trial of the Chinese vaccine COVID-19 vectorized with Ad5, which is working in the biotechnology firm CanSino Biologics and the Chinese army.
Similar to the Oxford-AstraZeneca vaccine, CanSino uses a vector-based viral vaccine, which is based on a weakened adenovirus. Interestingly, the adenovirus used is not the one present in chimpanzees but in humans. This could be a problem since exposure to human adenovirus has elicited immune responses in the past. The researchers had shared in their initial reports that people who were already exposed to adenovirus did not show robust immune responses compared to those who had not been exposed. In their phase 2 trial, almost 96 percent of people were able to build antibodies against SARS-CoV-2. Despite several concerns about the use of human adenovirus, they plan to enter Phase 3 testing.