COVID-19 has caused severe outbreaks in Canadian long-term care facilities (LTCFs). To evaluate the effect of mitigation measures in LTCFs including routine testing of staff and vaccination of staff and residents. Agent-based transmission model parameterized with disease-specific estimates, temporal sensitivity of nasopharyngeal (NP) and saliva testing, preliminary results of vaccine efficacy trials, and data from initial COVID-19 outbreaks in LTCFs in Ontario, Canada. Characteristics of staff and residents were included in the model with age-dependent risk of hospitalization and deaths, calibrated to the cumulative incidence of COVID-19 reported in these settings. Synthetic staff and resident populations. Routine NP and saliva testing of staff; vaccination of residents and staff. Daily incidence and attack rates in the LTCF using large-scale model simulations; estimates of hospitalizations and deaths and their 95% credible intervals. Weekly routine testing of staff with 2-day turnaround time reduced infections among residents by at least 20.3% (95% CrI: 18.7-21.8%), compared to baseline measures of mask-wearing, symptom screening, and staff cohorting alone. A similar reduction of hospitalizations and deaths was achieved in residents. Vaccination averted 2-4 times more infections in both staff and residents as compared to routine testing, and markedly reduced hospitalizations and deaths among residents by 81.4% (95% CrI: 80.6-82.2%), and 82.1% (95% CrI: 81.5-82.7%), respectively. Timelines of vaccine distribution and compliance rates with routine testing are key parameters affecting strategy outcomes. Routine testing of staff reduces silent transmission in LTCFs. Vaccination could have a substantial impact on mitigating disease burden among residents, but may not eliminate the need for other measures before population-level control of COVID-19 is achieved.