Outbreaks and Community Transmission During Ontario's Second Wave

Less than 10% of cases of SARS-CoV-2 transmission are linked to outbreaks, and settings of outbreaks are not representative of community transmission. The setting of transmission is unknown in approximately 60% of cases, and 40 to 60% of cases are considered to be due to community transmission. Restaurants with indoor dining are the most frequently visited venues in North America and external evidence indicates that gatherings in public and private settings must predominantly be responsible for community transmission. Outbreak data are important as marker to inform decision making, but not relevant to determine how community transmission can be reduced. Although controversial and challenging, restrictions appear to control surges in Ottawa, and are likely to have contributed to controlling surges in Toronto and Peel, even though to a lesser extent.

Slide Deck on Outbreaks and Community Transmission During Ontario’s Second Wave