Thank you for your thoughtful comment. You raised a good point in that mass vaccination may cause a drastic alteration in natural immunity, especially in children who will later form the next generation. Honestly, I don't have an answer to this issue.

Vaccinating children younger than 12 years may not be a good long-term strategy for natural immunity, but it may also be a good strategy in other aspects: For example, reducing incidences of chronic long-covid syndrome and further evolution of sars-cov-2 into something worse.

Moreover, at present, I'm not aware of any research showing that artificial immunity (by vaccination) is better than natural immunity in the long run. But please correct me if there's such research.