90% effective. It means that there’s a 10% chance that there are no guarantees of our immunity after injecting this vaccine onto our bodies. And also, they are not sure how long we would be immune to this virus after the vaccine. I would highly consider if it’s 99.9% effective and not 90%. Just my opinion.
indeed every human body has a different immune condition so that is what makes it not 100% usable for all humans because of this difference, vaccines have a long term meaning not everyone in the world is quickly given a vaccine, because if more than 14 days then covid 19 still has the potential to spread and what gets worse is that the corona can mutate against this vaccine so that they are immune and that will be terrible, hopefully it doesn't happen like that.