Sweden's case and death curve got crushed even though they never had a real lockdown. At most they banned public gatherings above 50 (so no concerts, no attendance in sporting events) and cancelled in-class instruction for students 16+. I've heard the reports that Sweden didn't actually achieve herd immunity (60+%). It was more like 13-14% immunity according to sero studies. But for some reason their cases and deaths dropped like a rock anyways. I don't think it's the summer because Brazil and India are getting ravaged by the virus. The Southern USA had lots of COVID in this heat.