When developing vaccines for novel viruses like coronavirus, where there is limited prior experience, there will be a learning curve and a need for humility regarding risk versus reward.

“one has to be thoughtful about risk versus reward trade-off with small n right yeah i think the surprise was that vaccine which was sort of a simian rotavirus basically that virus reproduced itself far less efficiently at the intestinal mucosal surface than did wild type virus natural virus there was no evidence that natural rotavirus caused any deception so why would this be true and the reason is is that interception really appeared to be around phenomenon it wasn't a winter phenomenon in the united states which was what rotavirus was you would expect to see a bump in the winter which you never saw so why would a vaccine do something that natural infection didn't do i think what we know now is that natural infection probably was a very rare cause of interception as was this vaccine and i guess the covet analogy is that here's a virus covet for which we had at least the gene structure in early january of this year which has already had a number of sort of clinical and pathological surprises which we are now about to counter with a series of vaccine strategies with which we have no commercial experience i think it's fair to say there's going to be a learning curve here so there has to be real humility”