> New vaccines usually take 6-7 years to complete clinical trials
Not necessarily. The yearly updated flu shot doesn’t for example. This case is similar, the novel technique itself was in development for a decade now with different parts having been clinically tested.
No they haven't. They were approved for emergency use only. New vaccines usually take 6-7 years to complete clinical trials.
https://www.modernatx.com/covid19vaccine-eua/