I literally posted an example where that worked in recent times, not to mention the historic examples of smallpox and polio (although the latter sadly still remains at like 99% due to anti-vaccine misinformation in the few areas that still have polio).
Vaccines work.
I think with the comment was saying is that we cannot eradicate a flu/covid disease by handwashing and masking. China has shown us you can control it with ruthless rules. And a more effective vaccine could do it, but there’s little precedent for a 100% effective respiratory vax.
Not COVID, because it is so highly infectious, but there is evidence that a strain of flu was eradicated because of COVID measures[1].