Covid-19Regional Covid-19 Thunder Bay District – One New Case; Total Active Cases is at Five By NetNewsLedger - August 20, 2021 995 Thunder Bay – COVID-19 – Thunder Bay District Health Unit (TBDHU) reports 1 (one) new COVID-19 case in residents in the TBDHU Region. The current number of active cases is at 5. The case listed today is from unknown exposure.