The flu vaccine: Information for patients and families

Definitions & Key takeaways

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Influenza or simply the flu is caused by influenza virus. Almost everyone has had the flu at some point, high fever, runny nose, sore throat, muscle pains, headaches, coughing, sneezing and feeling tired.
It's terrible. Good news is that it usually improves in a week but occasionally someone can go from being completely healthy to being seriously ill requiring hospitalization or even care in the ICU.
The flu spreads when a sick person sneezes or coughs and sends thousands of virus containing droplets into the local area.
If they're lucky, these viruses might land directly on another person's nose or mouth. But more often they end up landing on nearby objects like a table.
But the flu virus is hearty and it can survive for hours in the environment to make matters worse. A person may be contagious a day before their symptoms even begin and up to two weeks afterwards, even if they feel much better.
So while it's great that Debbie is back to work this week after recovering from the flu, it's not so great that Debbie brought contaminated donuts to share.
Thanks Debbie. Ok.
So if you don't want to feel like garbage with the flu for a week or get your friends families and coworkers sick. The most effective way to prevent influenza is through vaccination which can be done as an injection or nasal spray.
These vaccines usually contain a mix of three weakened or inactivated influenza virus strains that are predicted to be the ones that will dominate for a specific season.
And because flu viruses mutate rapidly, these vaccines are updated every year. So how well do they work?
Well, it depends first, high risk individuals like pregnant people, those with a chronic health condition or those under six months or over 65 years of age are more susceptible to the flu despite being vaccinated.
Second, since the vaccine is based on predictions, some years are better than others. On average, though the flu vaccine reduces the risk of illness by roughly half from about 10% to about 5% in terms of the likelihood of getting sick over the entire flu season.
That means that the average person may get the flu about one out of every 10 years without the vaccine and about one out of every 20 years with the vaccine.
So for any given year, you might decide that your risk of getting flu is quite low anyway. So it's not worth getting the vaccine.
But remember, the flu can do more than make you feel terrible. The flu can cause serious injury, even death, getting vaccinated also decreases your chances of you passing the flu to someone else like Debbie with her contaminated donuts.
Therefore, the more people in the community that are vaccinated against flu, the fewer people will contract and spread the flu.
This protects those that can't get vaccinated like infants under six months old. This is called herd immunity because the herd is protecting the weakest members to wrap up.
Of course, yearly flu vaccine is recommended for everyone, six months old and over with only a few exceptions, one, it's not recommended for people with a history of prior severe allergic reaction to the flu vaccine.
The benefit of the vaccine should be weighed with the risk of influenza complications in people with a history of Guillain Barre syndrome.
Otherwise, it's important to get a flu shot every year because of how much the virus can change from the year before. If you'd like to learn more about the flu, check out our influenza video on
The flu vaccine: Information for patients and families: Video | Osmosis