| CI | confidence interval |
| COVID-19 | coronavirus disease 2019 |
| EMS | emergency medical services |
| EMT-B | emergency medical technician–basic |
| EMT-I | emergency medical technician–intermediate |
| EMT-P | emergency medical technician– paramedic level (nebulized medication, supraglottic airway) |
| EMT-P+ | emergency medical technician–paramedic level (intravenous medication, endotracheal intubation) |
| HCW | health care worker |
| RG | regression coefficient |
| SARS-CV-2 | severe acute respiratory syndrome coronavirus 2 |