Ask an expert: COVID-19 and flu

How to protect yourself during the pandemic
A female patient wears a protective face mask while waiting for vaccination with a doctor in surgical gloves disinfecting her arm.

COVID-19 has put the spotlight on infectious diseases caused by viruses. Now the continuing pandemic is crashing headlong into the annual fall and winter increase in influenza or flu. So how can you protect yourself?

This question is especially critical if you are living with heart disease or stroke, as you face a higher risk of serious complications from either virus.

We called on two experts, both Heart & Stroke funded researchers, to answer questions about flu, COVID-19, heart disease and stroke. Dr. Craig Jenne is an associate professor at the University of Calgary and the Canada Research Chair in Imaging Approaches Towards Studying Infection. Dr. Thalia Field is an associate professor and stroke neurologist at the University of British Columbia.

If I get the flu, will that increase my risk of COVID-19?

Dr. Jenne: We don’t actually know. But we do know that it’s important to protect yourself from both viruses. A stressed body is more easily infected. And if another viral infection, such as flu, is damaging your lungs, you may have reduced defences.

Dr. Craig Jenne

It’s important to protect yourself from both viruses.

Dr. Craig Jenne Heart & Stroke researcher

While there has been no direct linkage between flu and COVID-19, we do know that people are better able to fight off most infections if they’re well rested, if they’re eating well, if they’re keeping stress low, and if they’re staying hydrated to keep airways from drying out.

Will a flu shot help protect me from COVID-19?

Dr. Jenne: The flu shot is a very effective method of avoiding influenza infection.

But the flu vaccine is not going to give you direct protection against COVID-19. These are unrelated viruses.

We are somewhat concerned about people having the potential to catch both viruses at the same time. A flu shot would definitely help protect against that.

What are the benefits of the flu shot?

Dr. Jenne: In an ordinary year, flu leads to about 12,200 hospitalizations and 3,500 deaths in Canada. The most vulnerable include people over 65 and those with other health conditions, including heart disease.

We know that the flu shot reduces hospitalizations by a significant number – in some years, more than 10-fold.

It reduces deaths. It reduces other flu-related complications, such as emerging evidence of heart attack and stroke.

And this year, avoiding flu will help take the pressure off the healthcare system, which is working very hard to deal with COVID-19 – for which we really don’t have other therapies.

Can the flu shot protect me from stroke?

Dr. Field: In general, systemic infection is associated with an increased risk of stroke. This can be due to factors within the body, including an increased risk of clotting or changes to blood vessel function or structure due to inflammation.

This can also be due to situational factors related to being sick, such as being more sedentary or disruptions in taking your medication.

Influenza in particular has been shown to be associated with an increased risk of stroke in both older and younger people.

There have been a number of studies looking at the association between flu shots and stroke. Although there is some inconsistency in the data, due to differences in how the research is conducted from study to study, in aggregate there is an association between decreased risk of stroke in people who receive a flu vaccination.

I’m worried about visiting a clinic or doctor’s office to get the flu shot.

Dr. Jenne: In several provinces, your local pharmacist is able to give you your flu shot. So you can call and make arrangements at places that are very low traffic.

You don’t have to go line up at a walk-in clinic or a hospital emergency department. You could book an appointment with your family physician to get a dedicated time. Medical offices and clinics are creating processes to administer flu shots efficiently and keep people distanced.

So there are many ways around this. We just have to look at our options, make a couple of phone calls and plan ahead.

What else should I be doing to stay healthy?

Dr. Jenne: While we continue to experience the pandemic, it’s important to follow public health guidelines to reduce your risk of exposure to the virus that causes COVID-19.

Plus, basic good health practices really do a good job of keeping viruses out. When we get run down, for example, or when our airways get dried out, it’s easier for a virus to get in.

So very simple things like getting enough sleep, drinking lots of water, and wearing a mask when requested, can actually be quite protective.

Talk to your healthcare provider or pharmacist for more information about the flu shot.

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