The flu vaccine: Information for patients and families

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 hardy—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 after 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 doughnuts 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, family 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 6 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.