According to the Centers for Disease Control and Prevention (CDC), the seasonal flu causes around 140,000 to 810,000 hospitalizations and 12,000 to 61,000 deaths every year in the United States.

Getting vaccinated can lower your chances of getting the flu. While you can get a flu shot anytime during flu season, the timing does matter.

In this article, we’ll help you understand how to time your flu vaccine for maximum protection.

In the northern hemisphere, the CDC recommends getting vaccinated between early September and late October.

The flu virus is around all year, but it spreads more easily from September through the spring, generally peaking between December and February.

It takes about 2 weeks to develop enough antibodies from the flu vaccine to protect you against the flu.

Protection fades over time, so getting vaccinated before September may leave you more vulnerable toward the end of flu season.

You can continue to get the vaccine through late winter to early spring.

Children aged 6 months to 8 years need two doses 4 weeks apart, so it’s best to get them started in early September.

Almost everyone aged 6 months or older can benefit from being vaccinated against the flu.

Some people are at an increased risk of serious flu complications, including those who are:

  • younger than 2 or older than 65
  • pregnant
  • living in a long-term care facility

People with the following conditions may also be at a higher risk of flu complications:

The flu vaccine is safe for most people who are pregnant or have a chronic health condition.

You can get a flu vaccine by injection or nasal spray.

There are several different vaccines, and some are recommended specifically for people:

  • 65 years and older
  • who are allergic to eggs
  • between 6 months and 65 years who aren’t allergic to eggs

If you’re currently feeling sick, it’s best to wait until you’re better.

Avoid the flu shot if you have a severe allergy to any of the ingredients that may be used in the vaccine, such as:

  • egg protein
  • thimerosal, a preservative
  • monosodium glutamate (MSG), a stabilizer that keeps vaccines from losing their potency
  • antibiotics, such as neomycin and gentamicin
  • polysorbate 80, an emulsifier which keeps the ingredients from separating
  • formaldehyde, which inactivates the flu virus

Babies under 6 months old shouldn’t be vaccinated.

If you’ve had Guillain-Barré syndrome, talk to your doctor before getting the flu vaccine.

The nasal spray contains a weakened live virus. It shouldn’t be taken by people who:

  • are younger than 2 or older than 50 years
  • are 2 to 4 years old and have asthma
  • are 2 to 17 years old and take medications containing aspirin or salicylate
  • are pregnant
  • have life threatening allergies to the flu vaccine
  • have a suppressed immune system
  • are in close contact with someone with a suppressed immune system
  • have taken antiviral drugs for the flu within the previous 48 hours

Talk to your doctor about the pros and cons of the nasal spray vaccine if you have:

  • asthma or chronic lung disease
  • a blood disorder
  • diabetes or other metabolic disorders
  • heart, kidney, or liver disease
  • a neurologic or neuromuscular disorder

The flu shot prompts your immune system to produce antibodies against a specific strain of the flu. If you’re exposed to this particular flu virus later, you’ll already have antibodies ready to fight off the virus.

It usually takes about 2 weeks to build up your immunity to a flu virus after you’ve been vaccinated against it.

You’ll have the most antibodies 1 to 2 months later. After this time, your protection begins to decline. That’s why you need a flu shot every year.

Each year’s vaccine is based on which strains are most likely to spread during that flu season.

The vaccine won’t protect you from every strain. But if you do get sick, it’ll likely be less severe due to the vaccine.

The 2020-21 flu season may be complicated by the COVID-19 pandemic. The overlap of these two viral illnesses threatens to overburden hospitals, which typically get an influx of patients who have complications from the seasonal flu.

Getting your flu shot can help lower your risk of flu complications that could put you in the hospital.

Most people have little to no reaction following the vaccine. There’s no live virus in the flu shot, so it can’t give you the flu.

Some people have a temporary reaction at the injection site, such as:

  • tenderness
  • redness
  • minor swelling

This usually clears up within a day or two.

Other side effects may include:

  • headache
  • lightheadedness
  • low-grade fever
  • muscle aches
  • nausea

These side effects are usually mild and should clear up in a couple of days.

Signs of serious allergic reaction usually occur within a few hours. These may include:

  • fainting
  • hives
  • hoarseness
  • rapid heartbeat
  • swelling of eyes or lips
  • trouble breathing
  • wheezing

According to the CDC, life threatening reactions are rare. If you have signs of a serious allergic reaction, call 911 or your local emergency services immediately.

Normally, you can get a flu vaccine at your doctor’s office, your local pharmacy, or even at a walk-in retail clinic.

Some employers even provide flu shots for their employees at their workplace.

Getting the flu shot may be a bit different in the 2020-21 flu season due to COVID-19 restrictions. You may need an appointment, so it’s best to call in advance to find out what you need to do.

In the United States, the flu shot is often free if you have health insurance. If you’re not sure whether it’s covered, call your insurance provider to find out if you need to pay anything toward the cost.

Even without insurance, you should be able to find a flu vaccine for under $50.

It’s a free preventive service under Medicare and Affordable Care Act (ACA) compliant policies.

If you don’t have health insurance or can’t afford a vaccine, you may still be able to find a low-cost or no-cost flu vaccine. To learn more about these options, try the following:

  • Call your doctor’s office, local hospital, and local community clinics.
  • Call local pharmacies, and be sure to ask about coupons.
  • Contact your state health department.
  • Visit, a searchable database of local vaccine providers.

The flu can strike anyone and can lead to serious, life threatening complications.

The best time to get your flu shot is from early September to late October. This timing offers you and your loved ones maximum protection for the duration of the flu season.

The vaccine is safe for most people. If you have an egg allergy or are allergic to substances that may be used in a vaccine, be sure to talk to your doctor or pharmacist about your concerns.