Table 2.
Predictors of testing prevalence and positive test prevalence over time
| Total Tests / Populationa | ||||||
| Timeframe | March 2nd to April 6th | April 6th to May 12th | May 12th to July 6th | |||
| IRRunadj (95% Confidence Limits) | IRRadj (95% Confidence Limits) | IRRunadj (95% Confidence Limits) | IRRadj (95% Confidence Limits) | IRRunadj (95% Confidence Limits) | IRRadj (95% Confidence Limits) | |
| White residents (%) | 1.0003 (1.0003–1.0003) | 1.0003 (1.0003–1.0004) | 1.000 (0.999–1.000) | 0.999 (0.999–1.000) | 1.0003 (1.0003–1.0003) | 1.000 (0.999–1.000) |
| Hispanic composition (%) | 0.999 (0.999–1.000) | 1.0001 (1.0001–1.0002) | 0.999 (0.999–1.000) | 1.000 (0.999–1.000) | 0.999 (0.998–0.999) | 1.000 (0.999–1.000) |
| Median age (years) | 1.001 (1.000–1.001) | 1.0007 (1.0005–1.0009) | 1.004 (1.002–1.006) | 1.005 (1.003–1.007) | 1.004 (1.003–1.005) | 1.004 (1.002–1.005) |
| COVID risk index quartiles | 1.002 (0.996–1.009) | 1.038 (1.029–1.046) | 1.038 (0.971–1.109) | 1.017 (0.939-1.101) | 0.834 (0.797–0.875) | 0.862 (0.814–0.913) |
| Positive Tests / Total Testsb | ||||||
| Timeframe | March 2nd to April 6th | April 6th to May 12th | May 12th to July 6th | |||
| IRRunadj (95% Confidence Limits) | IRRadj (95% Confidence Limits) | IRRunadj (95% Confidence Limits) | IRRadj (95% Confidence Limits) | IRRunadj (95% Confidence Limits) | IRRadj (95% Confidence Limits) | |
| White residents (%) | 1.000 (0.999–1.000) | 0.999 (0.999–0.999) | 0.999 (0.999–1.000) | 0.999 (0.999–0.999) | 0.999 (0.999–0.999) | 0.999 (0.998–0.999) |
| Hispanic composition (%) | 1.000 (1.000–1.000) | 1.000 (0.999–1.000) | 1.001 (1.000–1.001) | 1.000 (1.000–1.000) | 1.001 (1.001–1.002) | 1.000 (1.000–1.000) |
| Median age (years) | 0.999 (0.999–1.000) | 0.999 (0.999–1.000) | 1.000 (0.999–1.000) | 1.001 (1.001–1.002) | 0.998 (0.997 – 0.999) | 1.001 (0.998–1.003) |
| COVID risk index quartiles | 1.056 (1.037–1.077) | 1.010 (0.987–1.034) | 1.108 (1.083–1.133) | 1.031 (1.002–1.060) | 1.248 (1.164–1.338) | 1.135 (1.042–1.237) |
aPoisson regression performed, adjusted with a Pearson scaling factor to correct for overdispersion, log (population) used as an offset
bPoisson regression performed
Results shown for unadjusted and adjusted models. Models were adjusted for all variables shown. The total tests / population was calculated per hundred residents. A larger risk index quartile represents higher risk. Results for white residents (%), Hispanic composition (%) and Median age are reported in units of 10. IRR: incidence rate ratio