Influenza - The Flu

While in the winter of 2020/2021 there was essentially no flu transmission in Ontario, we do not expect that to be the case for the 2021/2022 winter.  We are already seeing a lot more viral respiratory infections than usual since August 2021, and therefore anticipate a lot of flu this winter.

Influenza is a viral illness.  It can cause serious illness, though most cases are just uncomfortable.  Every year the hospital system in Canada is strained with people who are sick with the flu, and every year our ICUs have most of their ventilators occupied with patients who have the flu (along with the more steady number of people in ICU for other reasons).  It tends to be most serious for children < 6 years of age and adults > 65 years, however everyone can get it, and everyone can pass it on to others.  While frequent hand washing and avoiding going out when sick help reduce the incidence, like COVID-19 it still seems to spread with the measures that we actually take.  This year with everyone masking in public and washing hands more frequently we may have a better year.  However, our hospitals may be less able to manage with the flu this year, and having the flu may make the spread of COVID worse - the flu is often an underlying cause for getting another infection, like a bacterial pneumonia.  You can get both COVID and Flu at the same time.

Why get immunized?  Every year, we see people who "never get sick" and feel like they are "dying" because they are so sick with the flu.  Often times they tell us that they don't get the flu shot because they never get sick, and/or they don't believe that it works.  The flu shot does work - but it doesn't work 100 % - like most things in medicine.  If you get the flu shot you are less likely to get the flu.  You are less likely to give the flu to someone you love (especially children and the elderly).  You are less likely to have to miss work.  This year in particular, getting sick means having to get tested for COVID-19, and isolation. 

It is safe to get immunized.  The only definite adverse effect noted with the flu vaccine compared to placebo injection, is pain at the site of injection, and the rare (1 in a million) chance of severe anaphylactic allergy.  If you have an egg allergy it is still safe to get the flu vaccine, but if you have an allergy to the flu vaccine then obviously you should not get it.

We do see people complaining of aches and pains and fatigue after having the flu shot (sometimes our patients will call these "flu like symptoms"), but we have also had people who have had those symptoms with prior flu shots, and with their next flu shot not get them. You cannot get the flu from the flu shot as there is no virus in it (except the nasal spray flu vaccine for kids).

There is a concern that Guillain-Barre syndrome (a serious neurological condition) could be an adverse effect, but this is quite rare and so it is hard to tell if it occurs more often in people being immunized compared to people not being immunized.  Certainly the risk of getting Guillain-Barre syndrome is more than 10 times greater in those who have contracted the flu than those who have been immunized (who have a similar risk to people who have not).  Nevertheless, we do not recommend the flu vaccine in those who  have been diagnosed with Guillain-Barre syndrome, particular if they had it within 6 weeks of an immunization in the past.