Get the facts on seasonal flu

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You can’t believe everything you hear about the flu and flu shot. There are a lot of myths out there, from how effective the flu vaccine is to how serious the flu virus can be. Get to know these key flu facts, so you can avoid the flu and stay healthy.

Flu Q&A

When is flu season?

Flu illnesses are most common during the fall and winter. Flu season typically starts in October and peaks December through February.

How does the flu spread?
The flu virus spreads mainly through tiny droplets made when people with the flu cough, sneeze, or talk. These droplets can land in the mouth or nose of other people nearby. And even more shocking, these droplets can travel up to 6 feet. Plus, the virus can survive on surfaces, such as doorknobs and tables, for up to 24 hours. And it can live on hard surfaces, like stainless steel and plastic, for up to 48 hours. So, don’t forget to wash your hands.
What should I do if I think I have the flu?

Flu and COVID-19 share many symptoms. Taking a COVID-19 home antigen test can help determine if you have COVID-19. Self-tests are the quickest and easiest way to find out whether you have COVID-19 — and stop you from putting others at risk. Even if your COVID-19 self-test is negative, stay home and isolate to avoid spreading your illness. Retest within 24 to 48 hours. 

For most healthy people, the flu will go away on its own within 7 to 10 days. But if you’re sick or at high risk for flu complications, contact your doctor. People at high risk for flu complications include young children, people 65 and older, pregnant people, and people with certain medical conditions

Can I take a test to see if I have the flu?
Most people don’t need to get tested for flu. But if you’re at high risk for flu complications and could need hospitalization, you should talk to your doctor about whether flu testing or treatment is right for you.
How long does the flu last?

For most people, the flu lasts 3 to 7 days. But cough, fatigue, and weakness can last for more than 2 weeks.

How long are you contagious?

People are typically contagious for about a week. It’s possible to give others the flu one day before you show symptoms. That’s because flu symptoms usually start about 2 days after the flu virus enters your body. In general, you can spread the virus up to 7 days after you start feeling sick.

Flu shot Q&A

How can I get a flu shot?
We offer many ways for Kaiser Permanente members to get no-cost flu shots. Visit to find the flu vaccination locations and hours for the Kaiser Permanente facilities closest to you. 
When should I get a flu shot?

It’s best to get vaccinated early in the fall, ideally by the end of October before flu season begins. Getting vaccinated later, however, can still be beneficial.

How does the flu shot work?

The flu shot helps your body make antibodies to fight the flu virus. It takes 2 weeks for a flu shot to start working and help protect you from the flu.

Why do I need a flu shot every year?
Flu viruses change each year. New flu vaccines are created every year to fight the latest virus. 
Does the flu shot have any side effects?

Any side effects are generally mild and go away within a few days. Common side effects include soreness or redness at the injection site, headache, fever, nausea, and muscle aches.

How effective is the flu vaccine?

Recent studies from the Centers for Disease Control and Prevention show that, on average, the flu vaccine can reduce the risk of flu by 40% to 60%.1 Effectiveness can vary based on how well the vaccine matches the strain of the virus each year. But even if you get the flu, the vaccine can still help make your symptoms less severe.

Can the flu shot give you the flu?

No. The flu shot can’t give you the flu. The vaccine doesn’t contain a live virus, so it can’t make you sick.

Is it safe for children to get the flu shot?

Yes. The flu vaccine is safe for children 6 months and older, and can even be life-saving. The flu can be very dangerous. Children 5 years and younger sometimes need medical care because of the flu.

Can I still get the flu if I get a flu shot?

Yes. It’s possible to get the flu even if you got a flu shot. This may happen because:

  • You caught the flu before the vaccine started to work. It takes 2 weeks for the vaccine’s antibodies to develop and protect you from the virus.
  • You got a virus that isn’t covered by the flu vaccine. The vaccine protects against 3 or 4 of the most common viruses expected during a specific year.
Are there “senior” flu vaccines made for people who are 65 and older?
People 65 and older should get a “higher dose” flu shot as now recommended by the Centers for Disease Control and Prevention (CDC). “Higher dose” flu shots currently include Fluzone High-Dose Quadrivalent, Flublock Quadrivalent, and Fluad Quadrivalent flu vaccines. Such “higher dose” flu shots are potentially more effective than “standard dose” flu shots in preventing severe illness, hospitalization, and death from the flu. If a “higher dose” flu shot is not available, people in this age group can get a “standard dose” flu shot since this would be better than not getting a flu shot. 
How can I get a “senior” vaccine?
Whenever one of the senior vaccines is available, we’ll automatically offer it to our members 65 and older. No prescription is required. If the senior vaccines aren’t available, we’ll instead offer our members 65 and older any flu vaccine that the CDC considers equivalent, as long as it’s licensed or approved for the right age group.

Flu and COVID-19 Q&A

What’s the difference between the flu and COVID-19?
The flu and COVID-19 are both respiratory illnesses, but they’re caused by different viruses. The flu is caused by influenza viruses, whereas COVID-19 is caused by a coronavirus called SARS-CoV-2. Some flu and COVID-19 symptoms are similar, so it can be hard to tell the difference between the two without getting a test to confirm. Visit our symptoms and treatment page to learn more about similarities and differences between the common cold, flu, and COVID-19.
Can I have the flu and COVID-19 at the same time?
Yes. According to the Centers for Disease Control, it’s possible to have the flu and COVID-19 at the same time. While details are continuing to emerge on how common this is, you can at least protect yourself from the flu by getting the flu shot. This is one of the many reasons why the CDC recommends that all people 6 months and older get a yearly flu vaccine.
Does the flu shot protect against COVID-19?
No. The flu shot doesn’t protect against COVID-19. However, the flu vaccine can help reduce your risk of flu illness, hospitalization, and death. It can also help lessen the severity of flu symptoms. If fewer people get the flu, care teams can focus their time and resources on providing COVID-19 patients with the care they need.
Does the COVID-19 vaccine protect against the flu?

No. The COVID-19 vaccine does not protect against the flu. However, the COVID-19 vaccine does reduce your risk of COVID-19 illness, hospitalization, and death. It can also help lessen the severity of COVID-19 symptoms.

Learn more about the COVID-19 vaccine and how to schedule an appointment at

Can I get a COVID-19 vaccine and a flu shot at the same time?

Yes, it’s safe to get the COVID-19 vaccine and a flu shot at the same time. 

Get the latest COVID-19 vaccine news at

Should a flu vaccine be given to someone with suspected or confirmed COVID-19?

No. If you tested positive for COVID-19, or believe you might have it, it’s best to wait before getting a flu shot. This will help prevent the spread of COVID-19 to anyone in the flu shot location — including other patients and health care teams.


Who’s at risk for flu complications? 

For most people, the flu is mild and goes away on its own. But some people can have a harder time fighting the flu. Their symptoms tend to be more severe or they can develop serious health complications like pneumonia, bronchitis, or respiratory failure. This is usually because they have weaker immune systems. 

People at higher risk for flu-related problems include:

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Children 5 and younger

Children under 5 often need medical care because of the flu.2

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Pregnant person

Getting the flu during pregnancy can increase the chance of miscarriage, premature birth, and low birth weight.4

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Adults 65 and older

In recent years, 70% to 85% of flu-related deaths occurred in people 65 and older.3

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People with chronic conditions

The flu can worsen chronic conditions like asthma, diabetes, heart disease, cancer, and HIV.5

The flu can be dangerous

David Bronstein, MD, a Kaiser Permanente doctor, dispels common flu myths and shares facts about the flu.


Flu activity near you

See what’s happening in your area. Get a weekly summary of flu activity in the United States from the Centers for Disease Control and Prevention.


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1 “Vaccine Effectiveness: How Well Do the Flu Vaccines Work?” Centers for Disease Control and Prevention,, accessed August 11, 2021.

2“Flu & Young Children,” Centers for Disease Control and Prevention,, accessed August 11, 2021.

3“Flu & People 65 Years and Older,” Centers for Disease Control and Prevention,, accessed August 11, 2021.

4“Flu During Pregnancy,” American Pregnancy Association,, accessed August 11, 2021.

5“People at High Risk for Flu Complications,” Centers for Disease Control and Prevention,, accessed August 11, 2021.