Still it doesn't make sense. Testing other epitopes could have taken very little extra time. In case of mRNA vaccines, just run some trials in parallel. And su

Still it doesn't make sense. Testing other epitopes could have taken very little extra time. In case of mRNA vaccines, just run some trials in parallel. And surely, it's better to hedge your bets. Otherwise, we might end up in the situation were all vaccines are useless as it's easy for strains to evolve countermeasures. That already seems the case of the Oxford vaccine...