Influenza (Flu)

Influenza, or the “flu”, is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and in some cases can cause hospitalization or death. This is especially true for young children, older adults, or those with underlying health conditions.

In the United States, flu season typically begins in the fall (October) and peaks in the winter (December – February) and can last as late as May.

DSHS encourages you to protect yourself, your family, and your community by getting the flu shot as soon as possible. We urge everyone six months and older to get vaccinated every flu season.

Influenza viruses are constantly changing and evolving. Each year, different strains of flu viruses circulate throughout communities, and they can change very quickly. Because of this, the flu viruses that make people sick one year may be different from the next. To match the changes in flu viruses, the vaccine needs to be updated each year to match the common and mostly likely to spread strains for the upcoming flu season. Even if the strains don’t change much from the previous year, protection from the flu vaccine doesn’t last forever. After you get vaccinated, your body builds protection, but the protection decreases over time. Annual vaccination ensures that your immune system is ready to respond to current flu viruses.

Even if you got a flu shot last year, you still need one for this year. The viruses have changed and your immunity has likely weakened. Getting vaccinated each year is the best way to protect yourself and those around you.

Influenza (Flu) Overview

Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. It affects the nose, throat, and sometimes the lungs. The flu can cause mild to severe illness. In some cases, it can lead to hospitalization and death.

Flu season in the United States typically runs from October to May with activity often peaking from December through February.

There are four types of influenza viruses: A, B, C, and D. Only types A and B cause seasonal flu in humans.

Each flu season, public health closely monitors the flu viruses circulating in their communities and recommend updates to the vaccine to match the most common strains. These strains change from year to year which is why the flu vaccine is updated annually to provide the best possible protection.

What Can I Do?

Stop the Spread

Wash your hands frequently. Cover your coughs and sneezes. Stay home if you’re sick.
Flu Prevention Tips

Person washing their hands with soap under running water.

Getting the flu shot is particularly important for

Influenza (Flu) Symptoms

Influenza (also known as the flu) is a contagious respiratory illness caused by flu viruses. It can cause mild to severe illness, and at times can lead to death. The flu is different from a cold . The flu usually comes on suddenly.

Flu Symptoms Include:

*It's important to note that not everyone with flu will have a fever.

If I (or Family Members) Get the Flu