The AZ vaccine needs to be able to enter your cells to work. That limits it to viruses that started off being able to infect you; we're not vulnerable to very m

The AZ vaccine needs to be able to enter your cells to work. That limits it to viruses that started off being able to infect you; we're not vulnerable to very many fish viruses. There's also the problem that we eat fish, and thus get exposed to fish viruses: one of the problems with using carrier viruses is you can already have immunity to them. If you do, the vaccine can be destroyed prior to it entering your cells, prior to it being able to induce those cells to create the spike protein that leads to COVID-19 immunity. https://www.medicalnewstoday.com/articles/covid-19-how-do-viral-vector-vaccines-work https://www.medicalnewstoday.com/articles/covid-19-how-do-vi...