OTTAWA -- Twenty-two cases of COVID-19 have been traced to one person who attended an indoor wedding in Ottawa last month with mild symptoms of novel coronavirus.

On Twitter, Ottawa Public Health (OPH) shared what it called a "real world contact tracing example – Wedding Cluster."

Public health says in September, one person with mild symptoms of COVID-19 attended a wedding with 50 people who weren’t physical distancing or wearing masks.

Within 15 days, 207 people were told to self-isolate and get tested for COVID-19. According to the Ottawa Public Health graphic, eleven households had at least one case of COVID-19.

The tracing tracked one person with COVID-19 in a school and one person with COVID-19 in a group home.  A COVID-19 outbreak was declared at the group home.

There is also a presumptive case of COVID-19 in a school.

"Kids missed school, their parents couldn't work and testing lines were long," said Ottawa Public Health. "Our. Actions. Matter."

Speaking on Newstalk 580 CFRA's Ottawa at Work with Leslie Roberts, Mayor Jim Watson said parties are the main driver of COVID-19 cases.

"These parties that we talk about, these AirBNBs or weddings, they're the bulk of the problems we're having in the city," said Watson.

"It's not the bars, restaurants and gyms. That's why I think our medical officer of health has been reluctant, as have I, to call for going back to Stage 2, which would close all these businesses and put them in great economic jeopardy."

Last week, Ottawa Public Health said one in four residents who tested positive for COVID-19 during the first two weeks of September were exposed to the virus at social gatherings in indoor and outdoor settings.

Dr. Jennifer LeMessurier told reporters that social interactions in indoor or outdoor settings is a "major driver of transmission in Ottawa and is happening at social gatherings."

"In places like homes, backyards, cottages, short stay apartments, hotels, restaurants and bars, during events with family and friends like birthday parties, weddings and house warmings."

The graphic, titled "COVID-19: Where are we exposed?" shows COVID-19 cases linked to lunchrooms and other shared employee areas at offices, indoor gatherings, daycare centres, outdoor gatherings like parks and barbecues, schools, travel and in bars and restaurants when dining with those outside of your household bubble.

COVID-19 in Ottawa