News Ontario adds highest number of COVID-19 cases in a 24-hour period SHARE ON: Wendy Gray, staff Sunday, Mar. 29th, 2020 Illustration of Severe Acute Respiratory Syndrome coronavirus 2, the cause of COVID-19 (Alissa Eckert, MS, Dan Higgins, MAMS) Ontario has 211 new COVID-19 cases. This is the highest number of new cases within a 24-hour period. Ontario now has 1,355 confirmed cases. Eight people have recovered, two more people have died bringing the death toll to 21, although two deaths have not been lab-confirmed. Over 40,000 people have tested negative.