TABLE 6.
Covariate-adjusted associations between school mask policy and SARS-CoV-2 infection-induced seroprevalence among individuals aged 12–17 years during the combined study periods (September 1–30, 2021 and December 15, 2021 to January 14, 2022)a
| Prevalence ratios (PR) | 95% CI | ||
|---|---|---|---|
| Mask Policy: No vs Full | 1.16 | 1.07 | 1.26 |
| Time Period: December vs September | 1.31 | 1.22 | 1.42 |
| Gender: Female vs Male | 1.01 | 0.95 | 1.07 |
| Region: Midwest vs Northeast | 1.14 | 1.04 | 1.26 |
| Region: South vs Northeast | 1.05 | 0.93 | 1.18 |
| Region: West vs Northeast | 0.90 | 0.82 | 0.99 |
| Race: NH Black vs NH White | 1.34 | 1.20 | 1.49 |
| Race: Hispanic vs NH White | 1.18 | 0.98 | 1.43 |
| Race: Hispanic and Black vs NH White | 1.26 | 1.07 | 1.47 |
| Race: Other vs NH White | 1.17 | 1.07 | 1.28 |
| Urbanicity: Non-urban vs Urban | 0.96 | 0.90 | 1.02 |
| Poverty Level: Above vs Below median | 1.04 | 0.96 | 1.12 |
| Education Level: High vs Low | 0.80 | 0.74 | 0.87 |
| County-level Vaccination Rate | 0.96 | 0.93 | 0.99 |
| County-level Cumulative Case Incidence | 1.24 | 1.09 | 1.41 |
Poisson regression models with robust variance estimation model were applied to estimate the association between school mask policy status and seroprevalence, adjusting for individual-level covariates (age and sex), area-level covariates (Census region, county-level urbanicity), ZCTA-level majority race/ethnicity, education and poverty-level, time-period, and the county-level vaccination rate and cumulative case incidence. All the covariates are categorical except vaccination rate and cumulative case incidence, which were included as continuous measures.