Flu season isn't over yet, doctor warns as infection dips in new year

Calgarians may be sneezing a bit less frequently in this new year but a public health doctor wants you to remember that flu season isn't over yet.

Influenza cases peaked the week of Nov. 11-17, according to Alberta Health Services. In 2017, the peak was the week of Dec. 10-16, a full month later.

Calgary also saw around 500 more cases of influenza in mid-December compared with a year earlier. Since then, cases have declined, said Dr. Jia Hu, Alberta Health Services medical officer of health for the Calgary zone.

"It's really important that people still think about the flu, even though a lot of the hubbub around the start of the flu season has come to a close," Hu said. "I think it's probably the single best thing you can do to prevent the flu."

The early start to the flu season was partly to blame for filling emergency rooms with flu-infected people, the Public Health Agency of Canada has said. The agency noted more children became ill than usual. Children are more vulnerable than adults to influenza and respiratory illnesses, such as pneumonia.

7 deaths, hundreds hospitalized

As of Thursday, influenza had killed seven people and sent another 437 to hospital in Calgary, AHS figures show. There have been 1,884 lab-confirmed cases of the flu in this region, making up 40 per cent of the total 4,634 cases across Alberta.

Hu did not know how many of the people who died or were hospitalized had been vaccinated against the flu.

So far, the bulk of the cases in Calgary have been of the H1N1 strain, rather than the H3N2 strain that was prolific last year, he said. H1N1 is associated with sometimes milder symptoms, he said, which may have led to fewer deaths and hospitalizations.

"There's a lot of things that might be going on, so the strain that's been circulating is one potential issue. Another thing is the vaccine might be a lot more effective this year than last year," Hu said.

"There's a lot of sort of random chance — depends who gets the flu, what else they're sick with — but I'm certainly really glad to see that the number of deaths does appear to be a lot lower than they were last year at this point."

The 2017-18 season was considered a particularly bad time for the flu. Fewer than a third of Albertans got vaccinated, Hu noted, and more than 9,000 lab-confirmed cases were reported. 

Previous seasons saw fewer cases: under 4,500 cases in 2016-17 and more than 5,300 in 2015-16.

Still time to vaccinate

Alberta Health Services describes the vaccine as a good match, and measures the efficacy of it throughout the season. The agency gets statistics early in the new year, Hu said.

This year's vaccine covers four strains of influenza, so if you've caught one already, the vaccine will help you fight off the other three or lower the severity of infection, he said.

By avoiding the flu, you also protect those around you who might be more vulnerable to the illness, including children, seniors and people with pre-existing illnesses, such as asthma.

The influenza vaccine is free for anyone over the age of six months in Alberta, including to non-residents. AHS offers an online tool to look up a nearby vaccination site. You can also call 811 or visit pharmacies, walk-in clinics and doctor's offices.

This year's vaccine has been described as a promising match to various viral strains by medical experts. The vaccine cannot cause the flu but some may experience mild side-effects such as a headache or achy muscles.

• MORE CALGARY NEWS | Calgarians continue building new careers and new lives outside of oil and gas in 2019
• MORE CALGARY NEWS | Calgary cyclist charged in death of 75-year-old pedestrian
• Read more articles by CBC Calgary, like us on Facebook for updates and subscribe to our CBC Calgary newsletter for the day's news at a glance