The hospitalization numbers show the majority of them were under 1 year of age, who would not be attending school. This according to your link [2] >> Among 95

The hospitalization numbers show the majority of them were under 1 year of age, who would not be attending school. This according to your link [2] >> Among 95 children aged <1 year with known hospitalization status, 59 (62%) were hospitalized, including five who were admitted to an ICU. The percentage of patients hospitalized among those aged 1–17 years was lower (estimated range = 4.1%–14%) And of course the number of children infected would be much lower than "all 74 million".