Do you think the following is broadly feasible?
Age 4-5 -- To comply with local school mandates, a child gets a full course of COVID vaccine (to include a third shot 6-12 months after the first two).
Age 6 -- Child's vaccine-induced antibodies have waned to essentially nil.
Age 7 -- Child is exposed to endemic COVID (a variant very close to Delta in all aspects).
Child's adaptive immune system kicks in the absence of right-now antibodies. The infection thus has a bit of lead time to set in, but not enough to cause more than annoying symptoms for a few days.
Age 8 -- Child is again exposed to endemic COVID, much like last time. Another Delta-like variant, no major changes in transmissibility, level of illness, etc. Pretty much the same thing happens as the year prior.
Age 10-18 -- Child is exposed to endemic COVID an average of twice a year. The worst of the symptoms are indistinguishable from what would've been considered a cold prior to 2020. Some of the infections are even asymptomatic altogether.
Age 19+ -- Person receives an inadvertent "booster infection" every year or two or three. Congratulations, COVID now joins
the legacy coronaviruses as being yet another vector for the common cold.
...
The idea is that instead of receiving dedicated booster COVID vaccines throughout the child's life, the repeated exposures to Delta-like variants of COVID essentially serve the purpose of booster shots. My understanding is that
this is hypothesized to have already happened with other coronaviruses, causing a serious pandemic at first, then settling into a manageable endemic illness later on.
I see your point about waning immunity in adults as observed in 2021. Is it meaningful that it's been waning adults
who have not been successfully fighting off SARS-CoV-2 all of their lives? If us middle-aged folks had first caught COVID as toddlers, and then have continued to have frequent exposures to it (assuming no game-changing variants) throughout our lives ... wouldn't we be a lot better off now?