In the news – CityNews (+ flu stats!)


For Jude, For Everyone was on CityNews on Wednesday, October 19th! I’ve had a few questions about the numbers shown in the video and wanted to clarify.

The numbers on the screen represent a specific subset of deaths from participating labs where influenza was the only condition found, however the Government of Canada and Statistics Canada both estimate an average of 3500 flu deaths each year in Canada. The Ontario Ministry of Health also reports that number, and also mentions an average of 1365 annual flu deaths just in the province. So here’s the question – why are the numbers so different? And I had the same question, so I asked people at each agency and also ran the information by doctors to confirm what I was understanding from the responses from these agencies.

City reported the numbers posted on the Public Health Agency of Canada, which gave a number of flu deaths by flu season. These numbers are not wrong – but they are not representative of the full picture of influenza in Canada. As I mentioned above, they represent only cases where there was only influenza. So why isn’t that the whole picture? First what we need to understand is that influenza is primarily a respiratory illness, and in cases where influenza becomes dangerous or lethal, it typically has caused pneumonia. In fact, it’s usually the pneumonia as a result of the influenza that leads to the cases becoming so serious. So let’s run some numbers. First, we have to address the difference in reporting periods. The PHAC reports by flu season and Statistics Canada collects data by calendar year. Here are the numbers as listed:


2011-2012          104
2012-2013          317

Statistics Canada:

2012:                   407       (influenza only)
2012:                   5694     (influenza and pneumonia together)

So simply by including with influenza the condition that frequently develops as a result of influenza and typically leads to influenza becoming more serious, we start to get a better idea. The first set of numbers is stripped down, while the second is expanded to include a more comprehensive view of the flu. And these numbers are before we begin to include other health issues, and that’s where reporting can get a little fuzzy and it makes it difficult to nail down a firm number – giving us estimates. Let’s break that down.

If a person with a heart condition gets the flu, and the flu triggers heart failure, what is the cause of death? That depends entirely on the physician filling out the death certificate and the way the coroner reports it. The same is true with health conditions across the board, including conditions like asthma or cancer treatment. The actual reporting includes a lot of variables, giving us blurred lines.

I admit that I personally find this frustrating – when it comes to science I like numbers. I like to point to an exact number and let it tell its own story. What I’ve learned when it comes to medicine, though, is that facts and numbers are frequently nuanced, and I’ve found this to be especially true with influenza. It’s rare for influenza to kill all on its own – it typically becomes lethal in combination with another already existing condition (like heart disease) or with a condition that occurs *because* of the influenza (like pneumonia).

I also recognize that there’s no clear way that the PHAC numbers make sense in the Statistics Canada numbers, and while speaking with Statistics Canada and running numbers we were unable to come up with PHAC’s exact result. PHAC directed me to Statistics Canada as their source, and were unable to give me further information, so I apologize for any lack of clarity on that point. I tried, but despite hours of phone calls I was unable to find anyone to connect those particular dots, so we can only go with the facts and without the lines between them.

So that leaves us with approximate numbers representing real people.