The non-pharmacological measures to contain the COVID-19 pandemic implemented in 2020 significantly impacted child admissions for respiratory diseases. This study aims to evaluate the impact of these measures on the incidence of child admissions after the resumption of school activities. Methods: This is a longitudinal study, conducted by analyzing pediatric hospital admissions data. It included data on patients diagnosed with bronchiolitis, asthma, or pneumonia. The period studied was from January to July of 2019, 2020, and 2021. Poisson regression models with robust variance were used to obtain relative risk and the respective 95% CI. For statistical significance, p <0.05 was used. Results: A total of 4024 pediatric admissions due to the diseases covered were recorded during the period studied. The reduction in admissions and costs in 2021 compared with 2019 was 56.99 admissions/100,000 children and 56% lower, respectively. Conclusion: Even during the period of relaxation of the non-pharmacological measures to contain the COVID-19 pandemic, there was a significant and clinically important reduction in the number of admissions due to respiratory diseases in children. The maintenance of the reduction in admissions indicates that these measures can have a highly important impact on infant health even after the resumption of school activities.