The NPR stories that I’ve listened to recently are saying that the vaccine is likely to continue to evolve over the first few years. That the first one approved may not give full immunity (ie it helps reduce the severity of infections) and it may only work in 60% of cases. But, given the speed at which this is being developed that is a pretty reasonable goal. We also won’t know how long it works and we may find out a year after it’s first release that 2 doses are required.
People often interpret that kind of uncertainty to mean that scientists don’t know what they are doing. But the goal of science, in this case at least, is to reduce the uncertainties that affect epidemiological management as quickly as possible. The uncertainties that will remain when the vaccination first roles out will be about subsequent decisions, not whether the vaccine provides some benefit that out weigh the possible negatives. Most people just can’t handle uncertainty or don’t understand it.