There are definitely benefits to vaccine diversity. The Oxford ChAdOx1 virus involves putting a modified chimp adenovirus into people. People don't have immunity to chimp adenovirus, so it infects them and delivers the spike protein, which elicits immunity. But that might also elicit immunity to the chimp adenovirus! If that happens, then a later does of the vaccine - say, for a new strain of SARS-CoV-2 in a year or two - might not be as effective, because immunity to the chimp adenovirus will stop the vaccine delivering the spike. In that case, having a different way to deliver a vaccine will be a life-saver.
Indeed. Maybe someone with more expertise can chime in — it's not clear to me if getting a vaccine with the chimp adenovirus backbone would preclude the possibility of getting another vaccine based on that backbone in the future (because of immunity to the backbone).
There are definitely benefits to vaccine diversity. The Oxford ChAdOx1 virus involves putting a modified chimp adenovirus into people. People don't have immunity to chimp adenovirus, so it infects them and delivers the spike protein, which elicits immunity. But that might also elicit immunity to the chimp adenovirus! If that happens, then a later does of the vaccine - say, for a new strain of SARS-CoV-2 in a year or two - might not be as effective, because immunity to the chimp adenovirus will stop the vaccine delivering the spike. In that case, having a different way to deliver a vaccine will be a life-saver.