Toronto’s top public health official says that it is just “not feasible” to expect the number of COVID-19 cases in the city to go down to zero and that it is more likely that there will be an increase in infections as students return to the classroom.

At one point earlier this month Toronto’s seven-day moving average of new COVID-19 infections had declined to 15.9 but it has risen steadily since then and now stands at 25, prompting Toronto Public Health to downgrade virus spread and containment to yellow from green in the latest update to its dashboard on Tuesday, suggesting that the area needs attention.

Speaking with reporters during a regular briefing at city hall on Wednesday, Medical Officer of Health Dr. Eileen de Villa said that the recent increase in cases is a “concern” but is not altogether surprising in the context of the broader reopening of the economy.

She said that while some cities, including Mississauga, have seen days in which the number of new infections was zero it is just not realistic to expect Toronto to get to that point anytime soon.

“In a perfect world we would see a decline until we have no new cases. This is not feasible right now given the size of our city, how contagious the virus is and because work is still underway to develop effective treatments,” she said. “The reality is that there are many months of this pandemic still ahead of us.”

There have been 198 new cases of COVID-19 confirmed in the city over the last week, including 23 on Wednesday.

De Villa said that while the numbers are down considerably from May when the city was regularly reporting nearly 200 new infections each day, the “virus is still here” and people still need to be following public health advice.

That, she said, means wearing a mask, keeping a distance of at least six feet from other people and regularly washing your hands.

She also encouraged Torontonians to limit get togethers with people outside their bubble to locations like a park or a backyard, where distance can be more easily kept.

“We are at a critical time in the pandemic and I need your help,” she said. “I am asking you to listen and to take note so you can help protect each other so we don’t lose our progress in fighting this virus. We are going to be living with this virus for the foreseeable future so it is critical that everyone understands that this is a marathon and not a sprint. We still have a long road ahead of us and we need to be careful.”

On Wednesday, 20 of Ontario’s 34 public health units reported no new cases at all. The 23 cases reported by Toronto Public Health was the highest number in the province.