John Maynard Keynes said that in an economic downturn, people should collectively spend more to avoid a deeper recession. But he also admitted that they, instinctively, tend to do the opposite and instead save more. We must avoid falling victim to the paradox of thrift.
A vaccine is not a fancy motorised scooter or a piece of operating software where a minimum viable product or MVP will do. This is not something that can be fixed on the fly after it has been injected into millions.