Get the facts on seasonal flu

Most people get the flu during fall and winter. Flu season typically starts in October. Depending on the year, the flu peaks — becomes the most widespread — sometime between December and February.

The flu virus spreads mainly through tiny droplets made when people with the flu cough, sneeze, or talk. These droplets can travel up to 6 feet. They can land in the mouth or nose of other people nearby. Plus, the virus in these droplets can survive on most surfaces for up to 24 hours. It can live on hard surfaces, like metal doorknobs and plastic buttons, for up to 48 hours. So don’t forget to wash your hands!

For most healthy people, the flu will go away on its own within 7 to 10 days. But if you’re very 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 . 

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 get tested.

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

You can infect other people 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 for up to 7 days after you start feeling sick.

We offer many ways for Kaiser Permanente members to get no-cost flu shots. Click here to view locations close to you where you can get a flu shot.

It’s best to get your flu shot by the end of October, before flu season begins. 

Getting it later can still help. It takes approximately 2 weeks for your body to create antibodies to the flu after getting the flu shot. The flu usually becomes widespread in winter.

To be best protected from the flu, children 6 months to 8 years old need two doses of flu shot this season if:​

• It’s their first time getting the flu shot.
• Your child previously received only one dose of flu shot.
• Their flu vaccination history is unknown.​

The second dose needs to be given at least 4 weeks after the first dose.

The flu shot helps your body make antibodies to fight the flu virus. It usually takes 2 weeks for your body to make enough antibodies to help protect you from the flu.

The flu virus changes each year. New flu vaccines are created every year to fight the latest virus. Plus, the immunity you get from a flu shot only lasts about a year.

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 (CDC) show that the flu vaccine can reduce your risk of getting the flu by 40% to 60%.¹ The effectiveness of the flu shot varies based on how well the vaccine matches the current virus, your age, and your general health. 

But even if you catch the flu, getting the flu shot can 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 lifesaving. The flu can be very dangerous. Children 5 years and younger sometimes need medical care because of the flu.

During the 2023-24 flu season, children who got a flu vaccine were up to 67% less likely to visit a health care provider because of flu, and up to 61% less likely to be hospitalized with flu.⁷

For full protection, kids 6 months to 8 years old need two doses of flu vaccine this season if:​

• Getting vaccinated for the first time
• Previously received only one dose of flu vaccine​
• Flu vaccination history is unknown.​

The second dose needs to be given at least 4 weeks after the first.

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 antibodies to develop and protect you from the virus.
• You got a virus that wasn’t covered by the flu vaccine. Each year the flu shot is designed to protect you from the coming season’s most common expected virus. Sometimes there’s a mismatch between the vaccine and the virus.

People ages 65 and older are now recommended by the CDC to get a high dose flu shot. High dose flu shots have been shown to be potentially more effective than standard flu shots in preventing severe illness, hospitalization, and death in older adults.² 

If a high dose flu shot is not available, people in this age group should get a standard flu shot. This is better than not getting a flu shot at all. 

If one of the senior vaccines is available, we will automatically offer it to our members ages 65 and older. No prescription is needed. If no senior vaccine is available, we will offer our members ages 65 and older a flu vaccine that the CDC considers equivalent. 

Both the flu and COVID-19 affect your respiratory system — your lungs and airways — but they’re caused by different viruses. The flu is caused by influenza virus. 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. Visit our symptoms and treatment page to learn more about telling the difference between the common cold, flu, and COVID-19.

Yes. According to the Centers for Disease Control, it’s possible to have the flu and COVID-19 at the same time. You can protect yourself by getting the flu shot and the latest COVID-19 vaccine. 

No. The flu shot doesn’t protect against COVID-19. However, the flu vaccine can help reduce your risk of hospitalization and death from the flu. It can also make flu symptoms less severe. 

No. COVID-19 vaccines do not protect against the flu. However, COVID-19 vaccines do reduce your risk of hospitalization and death from COVID-19. They can also help lessen the severity of COVID-19 symptoms.

Learn more about COVID-19 vaccines and how to schedule an appointment at kp.org/covidvaccine.

No. There is no evidence that getting a flu shot increases your risk of getting COVID-19. 

Yes. It’s safe to get a 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 workers.