TABLE 5.
Covariate-adjusted associations between school mask policy and SARS-CoV-2 infection-induced seroprevalence among individuals aged 5–11 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 | 1.21 | 1.10 | 1.32 |
| Time Period: December vs September | 1.06 | 0.93 | 1.22 |
| Gender: Female vs Male | 1.01 | 0.94 | 1.10 |
| Region: Midwest vs Northeast | 1.35 | 1.18 | 1.55 |
| Region: South vs Northeast | 1.24 | 1.07 | 1.43 |
| Region: West vs Northeast | 1.12 | 0.95 | 1.32 |
| Race: NH Black vs NH White | 1.38 | 1.19 | 1.60 |
| Race: Hispanic vs NH White | 0.88 | 0.67 | 1.16 |
| Race: Hispanic and Black vs NH White | 1.38 | 1.22 | 1.57 |
| Race: Other vs NH White | 1.01 | 0.91 | 1.13 |
| Urbanicity: Non-urban vs Urban | 0.99 | 0.90 | 1.08 |
| Poverty Level: Above vs Below median | 1.02 | 0.91 | 1.14 |
| Education Level: High vs Low | 0.77 | 0.68 | 0.88 |
| County-level Vaccination Rate | 1.09 | 1.03 | 1.15 |
| County-level Cumulative Case Incidence | 1.36 | 1.15 | 1.61 |
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.