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COVID-19 versus influenza: should we be more worried?

This article is one of the many resources offered within our Health Navigation Platform, giving your members access to credible health information. In it, Chief Medical Officer Dr. Michael Szabo compares statistics on influenza and COVID-19, answers the most asked questions on the pandemic and tells us what we know so far.

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As a physician, I cannot go anywhere these days without being asked about my opinion on COVID-19.

It’s a unique situation: a new virus, that we have incomplete knowledge about, has the potential to spread significantly in Canada. Experts are currently estimating that, if we have a full-fledged pandemic, as many as 30–60% of us could become infected. We all want to know the risks and we want to be prepared.


The flu as a benchmark

The majority of questions I get from people are centered around the comparison between COVID-19 and influenza. Influenza spreads around Canada every winter so most of us are used to it. We generally don’t panic about it, but we know to be careful. I think people want a benchmark to compare COVID-19 to and that is very understandable.

Should we be more concerned about influenza than COVID-19? Well, yes and no.

  • Influenza infects 1 billion people worldwide annually and kills 250,000 to 500,000. That’s a lot of people.
  • In Canada alone, about 3500 people die each year of influenza.
  • 5–10% of adults and 20–30% of children get infected each year.
  • Approximately 0.1-0.2% of people who get influenza will die.

There are also a host of other problems that influenza can cause that do not cause death but can seriously impact your life—myocarditis, transverse myelitis, and Guillain-Barré syndrome to name a few. Influenza is a serious problem and should be a concern for the average person because there is a pretty reasonable chance you can get it. Thankfully, we have a vaccine that can prevent 40–60% of cases. Such is not the case with COVID-19.


What we know on COVID-19 so far

At this time, COVID-19 is not circulating in the general population at any level even remotely comparable to influenza—but that could change and that is the concern.

The preliminary numbers for COVID-19 should give us pause; however, they should also be interpreted correctly.   Details are very important in analyzing these complex matters.

The best data we have on COVID-19 is from a Chinese study that included approximately 44,500 confirmed infections. 81% of patients presented with mild symptoms similar to a cold or flu. 14% of patients developed severe symptoms such as pneumonia and needed to be hospitalized. 5% required critical care support, meaning they were in the intensive care unit and on a ventilator. The overall death rate was 2.3%.

As I said earlier, the details here are important. This study looked at those with laboratory-confirmed cases who saw a doctor. It does not include the many people who had no symptoms at all but were infected. It also does not include those who had mild symptoms who never saw a doctor at all, as would often be the case in China. It is also important to understand how officials are recording deaths in China, as it may be different than how we record them here. Some people may not have actually died of the virus directly.

The numbers of very ill individuals, which is around 20%, is alarming but it may not reflect what we end up seeing here in Canada. It is quite possible these numbers are inflated because of how the data was collected. Nevertheless, it is important to be cautious. It’s not the time to draw sweeping conclusions. We need to patiently wait for our understanding of this virus to increase and temper our tendency to panic in the meantime.


Can COVID-19 be transmitted without symptoms?

Another point I am continually asked about is the concern that COVID-19 is being transmitted in the community from people who are infected but have no symptoms. We still do not know that this is truly the case.

Again, the details are important here. While someone may appear to have no symptoms, further in-depth questioning reveals that they do indeed have a bit of a headache, a stuffy nose or achy muscles. For someone to transmit the virus without symptoms in any kind of significant way, they would need to be shedding the virus out of their body in the absence of any sneezing or coughing to get it out there.

The likelihood that this type of transmission could contribute significantly to the spread of the virus in the community is extremely low. Time and careful scientific study will confirm our assumptions.


What’s the verdict?

Influenza is certainly a concern for all Canadians, as it should be. It is more prevalent than COVID-19 at the present time and our risk of acquiring it and having a negative outcome should not be dismissed.

COVID-19 is concerning as well, particularly if the pandemic that has been predicted comes to be.

Be informed, be prepared, and protect yourself.

 

About the Author

Dr. Michael Szabo is the Medical Director of Novus Health. He is an emergency physician at University Health Network in Toronto and a lecturer in the Department of Family and Community Medicine at the University of Toronto. Dr. Szabo has 25 years of experience providing front-line medical care. He has extensive experience with providing executive and concierge health care as well as expert medical second opinions.

 

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