start at 2:45 in this clip (youtube) were he admits that that flu vaccine isn't directly so effective in older people (young people who get it cut down on the spread which benefits older people).
(3:15)
GATES: You know, if we have, you know, one in 10,000 side effects, that's, you know, way more— 700,000—you know, people who will suffer from that. So really understanding the safety at gigantic scale across all age ranges—you know, pregnant, male, female, undernourished, existing comorbidities—it's very, very hard. And that actual decision of, “OK, let's go and give this vaccine to the entire world,” ah, governments will have to be involved because there will be some risk and indemnification needed before that can be decided on.
So says the, you know, college drop out and NON-medically trained health ‘expert’.