Look at the flu vaccine market for comparison.Now that we've been chasing the flu with vaccines , it mutates and then we have to come up with another vaccine for the new strains. If the Dengue virus behaves in the same fashion then we're really going to have a problem. With NNVC's approach the virus would have to mutate away from the method it uses to attach to the target cells and once that happens it has lost the ability to attach period. If anything , I would see the market getting larger not smaller.
Sanofi vaccine for dengue is still in early trials. No Dengue vaccine has ever emerged from Phase III trials, in spite of equal promise i9n the past. The issues of that type of vaccine only appear after expended population studies. When Sanofi's tetravalent dengue vaccine is finally at the NDA stage I will take notice then.
The one indication that is different from previous Dengue vaccines is that Sanofi is building an industrial scale facility specifically for Dengue Phase III trials and plans completion by December.