Top 5 Takeaways Test to Stay (TTS) Implementation: 90 schools in Lake County, Illinois, implemented the TTS strategy during fall 2021, allowing close contacts with masked COVID-19 exposures to remain

Top 5 Takeaways TTS Adoption: One in five public schools in Los Angeles County adopted the Test to Stay (TTS) strategy, allowing students exposed to COVID-19 to remain in school

Top 5 Takeaways High Hospitalization Rates: 77.9% of children and adolescents hospitalized during the study period were admitted for acute COVID-19. Viral Coinfections: Approximately one third of children under 5

Top 5 Takeaways High Vaccine Effectiveness: The Pfizer-BioNTech vaccine showed 92% effectiveness in preventing SARS-CoV-2 infection among adolescents aged 12–17 years under real-world conditions. Study Design: A prospective cohort study