This is a video of his concerns
https://rumble.com/vhsm3h-nobel-laureate-luc-montagnier-warns-covid-vaccine-may-lead-to-neurodegenera.html
1:16 - 1:27:
"I also want to say that I never, never said that everyone will die from the vaccine, but that a certain number of people who take the vaccine will suffer from it. That's impermissible."