Lancet journal published the phase 2 trial results of the Chinese Ad5-vectored COVID-19 vaccine, which is being worked upon by biotech firm CanSino Biologics and the Chinese military.

Similar to the Oxford-AstraZeneca vaccine, CanSino makes use of a viral vector-based vaccine, which is based on a weakened adenovirus. Interestingly, the adenovirus used is not the one that is present in chimpanzees but humans. This could be an issue as in the past exposure to human adenovirus has thrown off immune responses. The researchers had shared in their initial reports that people who were already exposed to adenovirus did not show robust immune responses in comparison to those who had not been exposed. In their phase 2 trial, almost 96 per cent people were able to build antibodies against SARS-CoV-2. Despite several concerns over the use of human adenovirus, they are planning to enter the phase 3 trial.