I'm not suggesting to include new strains on the fly while they are discovered without trials. The same way they had to do trials for Gardasil-9 after already h

I'm not suggesting to include new strains on the fly while they are discovered without trials. The same way they had to do trials for Gardasil-9 after already having Gardasil, they could do the same just with a wider cocktail. In the optimal case you would attempt the 100+ cocktail and don't have any unreasonable side effects from them. Of course if there is a single variant in there that causes side effects you would need a ton of trials to triangulate which one causes them, but there is no guarantee that that is necessary or that you wouldn't run into that variant when you just adding 5 new variants in an iteration.