>There's no data about prevalence of long-term symptoms after an infection yet

There's also no data about the prevalence of long-term symptoms of the covid vaccines, since it's literally impossible to test the 2-5 year effects of something that's only existed for one year, so by your logic should non-at-risk populations avoid taking that?

If the fear is long-term damage, then we must stay locked down and isolated for another two years to first wait for any real long term damage to show and then study it. With this mentality, what's the point of life? Might as well commit suicide, especially those grandparents which might not survive until then anyway.

It's not a binary choice between opening up now and staying in lockdown forever. We could wait a bit longer with opening up till more people are vaccinated, to reduce the risk of getting an infection for everyone (don't forget vaccines aren't 100% effective). We also could decide the immediate harm of lockdown outweighs the risk of long-term effects.

It's a complicated situation, and there's likely no perfect answer. However, it's definitely not as black-and-white as "if they don't get sick, they don't get sick", and such reductionist statements don't help make an informed decision.

Depends if the lock-downs are at your doorstep or at the border. The UK had a few opportunities to pursue a zero covid strategy but squandered them all.