I understand that the time it took Modena to go from the SARS-CoV-2 sequence to shipping doses for clinical trial was 44 days:
I don't know exactly what happened in that 44 days, but I am guessing it was things like synthesizing a DNA template, making sure that the protein would fold, maybe figuring out how to purify it, printing the shipping labels, etc.
If Modena (or Pfizer) wanted to switch their vaccine from the Wuhan strain to the B.1.1.7 strain, how fast could they get a B.1.1.7 variant dose into someone's arm? I presume it would be less than 44 days, but what's a guess as to the fastest it could happen (assuming they didn't have to go through trials again)? Is it just like two days to synthesize the template DNA? If not, what are the other steps they would need to go through?