I don’t know. If a medicine cures 99 % of all cases (or even 10 %) would you say it’s ineffective? I’d say it’s effective, but depending on the your overall goal, not effective enough (if you’d like to call it ineffective, it would be ineffective with respect to a certain macro outcome, not with respect to individual cases). At some minuscule percentage (let’s say 0,1 %) I would probably be tempted to actually starting to call it ineffective.
It would be to anyone thinking about this logically, but belief in the measures seems to have become like a religion to some. The craziest discussion I had about this was with a friend who insisted the number of administered tests for a given location hadn't risen in 2021. I showed them the official government stats but they still claimed there hadn't been a rise. When I sent them a graph they said they'd looked at it and it confirms there was no rise. The graph showed a clear rise, like line going straight up!
How do you even deal with this? I can have more rational discussions with fundamental Christians.