If your sole aim is the reduce infections then lockdowns clearly work.
But then you have to consider the harms of a collapsed economy, inactivity. Mental health, largely closed health system creating a future backlog of issues.
I wouldn’t be surprised when we look back in years to come we come to the conclusion they did more harm than good.
You have to also factor in when we lose a mother of three to undiagnosed cancer vs an 85 year old nearing their end of life, there is an issue... and the toll in this regards will be huge over the coming years.