Flu season arrives early in Ontario as H1N1 cases rise ahead of October

Flu cases are appearing across Ontario weeks earlier than usual this year, with infections climbing as the province typically prepares for late October.

"It's an early rise but it absolutely is a rise," said Isaac Bogoch, an infectious diseases specialist at Toronto General Hospital. Canada's positivity rate for the week of September 21 to 26 was 3.7 per cent, with Ontario at three per cent — higher the week prior.

H1N1 is the dominant strain circulating this year and tends to be milder on infected individuals and hospitals compared to H3N2, though Bogoch noted that "at an individual level, any flu can still cause tremendous harm and people feel really, really crummy."

Joseph Param, a Toronto family doctor, is seeing a surge in influenza cases among young adults at his practice. Those patients — the age group most likely to use public transit, shop in crowded spaces, and work out at gyms — are often assuming they have a cold and continuing their routines. "Instead of actually seeing their primary care provider and getting properly tested, they're assuming it's just a cold. 'Oh, I'll still go into work' or 'I'll still go to school'," Param said. "Oftentimes, that's where we see the spread."

Param attributes the early surge to climate change and varying weather patterns, as well as modified travel plans.

Flu shots are rolling out first to adults 65 and older, who account for the highest number of detections. The general public will have access to vaccines "a little bit later on in the month," according to Bogoch. Symptoms that distinguish flu from a cold include muscle or body pain, fever, and fatigue.