Covid and the lockdowns both might be causing the effect. So you have one group that has just Covid and then one group that has both. Then you compare the outco

Covid and the lockdowns both might be causing the effect. So you have one group that has just Covid and then one group that has both. Then you compare the outcomes and see if the just-Covid group has the effect too. But my comment was kinda tongue-in-cheek: How do you even find people not affected by this doom-n-gloom global news story?