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Informing School Strategies for Future Pandemics: The Epidemiological Evaluation of COVID-19 Testing and Vaccination Strategies in a Large Public School District in the U.S
23 Pages Posted: 5 Dec 2024
More...Abstract
Background: The Los Angeles Unified School District (LAUSD), the second-largest public school district in the U.S., implemented a comprehensive COVID-19 mitigation strategy in August 2021, including mandatory weekly testing and a phased vaccination program. This study evaluated COVID-19 transmission and the associations between mitigation strategies and positivity rates within the school population.
Methods: We conducted an observational cohort study using data from 12,766,036 COVID-19 tests carried out at LAUSD from January 1, 2021, to May 1, 2022. Weekly testing rates, COVID-19 positivity rates, and vaccination data were analyzed. Comparisons were made with broader Los Angeles County (LAC) data. We examined socioeconomic status (SES) disparities and their association with COVID-19 outcomes.
Findings: LAUSD’s average positivity rate was 0.58% during the Delta variant wave (July 1, 2021, to September 1, 2021) and increased to 10.13% upon return to school during the Omicron variant wave (January 1, 2022, to February 1, 2022). Higher vaccination rates correlated with reduced positivity: when the 12–18-year-old cohort reached a 40% vaccination rate, their positivity rates were 13.5% lower (95% CI: 4.1% to 19.7% reduction) than those of the 5–11-year-old cohort. Mitigation strategies eliminated SES disparities, and positivity rates did not differ across schools, except immediately after school breaks.
Interpretation: The findings suggest that comprehensive mitigation strategies combining frequent testing and vaccination can reduce the risk of transmission in schools. However, these associations should be interpreted cautiously due to study limitations: the observational nature of the data, potential uncontrolled confounders, and limited data on community spread and external factors influencing transmission. Insights from LAUSD's approach can inform future policies and operations in similarly complex educational environments.
Funding: Supported in part by Stanford School of Engineering COVID-19 Research and Assistance Fund, which had no role in study design, data collection, analysis, interpretation, or writing.
Declaration of Interest: We declare that the authors have no competing interests related to this work.
Ethical Approval: Ethics approval was obtained for this study through the Stanford Institutional Review Board (IRB), with an expedited review for secondary data analysis of LAUSD-collected COVID-19 test data. The study followed the STROBE Equator Network guidelines.
Keywords: COVID-19, School Mitigation Strategies, Testing and Vaccination, Public Health Interventions, Socioeconomic Disparities, Epidemiology, Educational Settings
Suggested Citation: Suggested Citation