Flu illnesses are most common during the fall and winter. Flu season typically starts in October and peaks December through February.
Get the facts on seasonal flu
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
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.
For most people, the flu lasts 3 to 7 days. But cough, fatigue, and weakness can last for more than 2 weeks.
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
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.
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.
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.
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.
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.
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.
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.
Flu and COVID-19 Q&A
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 kp.org/covidvaccine.
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 kp.org/covidvaccine.
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:
Children under 5 often need medical care because of the flu.2
Getting the flu during pregnancy can increase the chance of miscarriage, premature birth, and low birth weight.4
In recent years, 70% to 85% of flu-related deaths occurred in people 65 and older.3
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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Footnotes
1 “Vaccine Effectiveness: How Well Do the Flu Vaccines Work?” Centers for Disease Control and Prevention, cdc.gov/flu/vaccines-work/vaccineeffect.htm, accessed August 11, 2021.
2“Flu & Young Children,” Centers for Disease Control and Prevention, cdc.gov/flu/highrisk/children.htm, accessed August 11, 2021.
3“Flu & People 65 Years and Older,” Centers for Disease Control and Prevention, cdc.gov/flu/highrisk/65over.htm, accessed August 11, 2021.
4“Flu During Pregnancy,” American Pregnancy Association, americanpregnancy.org/pregnancy-complications/flu-during-pregnancy/, accessed August 11, 2021.
5“People at High Risk for Flu Complications,” Centers for Disease Control and Prevention, cdc.gov/flu/highrisk/index.htm, accessed August 11, 2021.