Ontario families are heading into another respiratory virus season but health experts say it is still too early to know whether the coming months will bring a mild wave of illness or another difficult flu season.
Data from Public Health Ontario shows that the positivity rate for COVID-19, RSV and influenza remains “low” overall but is starting to inch up for all three viruses.
The most recent data for the week ending Aug. 15 shows that COVID-19 positivity in Ontario was up to 1.4 per cent after dropping to as low as 0.4 per cent in July.
Last September, COVID-19 positivity hit nearly 10 per cent in Ontario, which is the highest level recorded over the past year.
Speaking to CTV News Toronto, experts say viruses like Influenza, COVID-19 and RSV typically become more active in the fall and winter as people spend more time indoors, while the return to school puts children in closer contact with one another.
Simple habits like washing your hands, getting vaccinated, and staying home when sick still offer the best protection against serious illness and spreading germs. However, experts say they cannot yet predict exactly when viral waves will arrive.
“It’s too early to really know,” said Dr. Shaun Morris, a clinician-scientist in the Division of Infectious Diseases at SickKids and a professor in the University of Toronto’s Department of Pediatrics. “Before the respiratory viral season starts, it’s not really possible to predict what it will look like.”
It’s more than just flu season
Morris said it is more useful to think of the coming months as a respiratory virus season, rather than simply “flu season.”
“The ones that we pay most attention to in the fall and winter are influenza, RSV, and SARS-CoV-2, which is the virus that causes COVID,” he said.
“We can reliably predict that each year there’ll be an increase in overall viral infections, not necessarily the distribution of which viral infection.”
In a statement to CTV News, Toronto Public Health also noted it is too early to predict exactly what this season will look like and noted that respiratory virus activity can change throughout the coming months.
In 2025, influenza activity in Ontario peaked in December when the positivity rate rose to 35.7 per cent.
“Last year was a particularly difficult influenza season, and activity began early,” the statement read. “As we head into the fall, TPH will continue to monitor respiratory virus activity and share updated information with residents through our Integrated Respiratory Diseases Dashboard.”
The return to school
The return to classrooms does not necessarily cause respiratory infections, Morris said. Instead, it has more to do with a seasonal shift that brings people indoors and into closer contact with one another.
“It’s not schools per se that’s the risk,” he said. “It’s just the natural season. People are spending more time inside, including in schools, and people are spending more time in closer proximity to numerous other people than they are during the summer.”
TPH recommends several layers of protection, including staying up to date on vaccinations, wearing a mask in crowded indoor spaces when appropriate, choosing well-ventilated spaces, washing hands and staying home when sick.
Vaccines can still make a difference
Morris said vaccination remains one of the most important tools available, even though vaccines do not prevent every single infection.
“Even if these vaccines may not prevent 100 per cent of infections, what they also do is they reduce the risk of an infection being very serious if you have it,” he said.
Ontario publicly funds the influenza vaccine for everyone six months and older while RSV prevention is available through vaccination during pregnancy or a monoclonal antibody product for infants.
TPH said this fall’s influenza and COVID-19 vaccination programs will be phased, beginning with people at higher risk of serious illness before expanding to the general public.
When illness needs medical attention
It can be difficult to determine whether someone has influenza, COVID-19 or RSV based on symptoms alone because the illnesses can look similar, Morris noted.
He said for parents, the focus should be on signs that a child is becoming seriously ill.
“It’s not so important what the virus is so much as what the symptom profile is that would dictate if someone needs to see a physician,” he said.
Warning signs include very rapid or laboured breathing, difficulty breathing, blue or dusky lips, extreme lethargy and dehydration. A child who is unable to keep fluids down or is not urinating should also be assessed by a doctor.
For families heading into the fall, Morris says to plan ahead, keep vaccinations up to date, wash hands and stay home or wear a mask when significantly sick.
“It’s very helpful to minimize overall transmission to stay home or wear a mask,” he said.
