cshwone:
Gurezaemon:
I've heard this likened to releasing a new year's model of car - all of the time-consuming safety checks have been carried out on the previous model, and small changes such as a different bonnet, grille, and door trim do not mean the car has to go back to step 1 for crash testing, etc.
And that approach worked well for the B-737 Max !!
The B-737 MAX was exactly the opposite. A significantly redesigned car, with a much larger motor, "smart" power steering to overcome the effect of the extra weight and make it drive like the previous model, but with a badge and grill to make it look like the previous model.
I'm not sure that it applies to these vaccines either? IIRC, they're the first mRNA vaccines to go into production?