I have read this a couple of times and am trying to convince myself that I must be misunderstanding it.
Hoping someone else tells me how!!
It’s simple lockdown everyone to avoid the high risk getting it or lockdown only the high risk and let the low risk catch it and go for here immunity while isolating only the high risk. The third option is isolating the confirmed infected symptomatic or not and anyone who had any form of contact with them no matter how brief for a full incubation period of at least 14 days. The third approach is how Japan, Taiwan and Korea have kept their numbers so low.