Flu shot questions answered: Who should get them and when

The flu shot helps your immune system recognize to protect against the strains of flu viruses experts believe will most likely spread in the coming flu season. While effectiveness can vary from year to year, the flu shot can reduce your risk of getting sick or make illness milder should you get the flu. You need a flu shot every year because flu viruses change and protection from vaccination decreases over time.

Several factors can determine the effectiveness of the flu shot, including timing. We usually see the first flu cases in October, and the season peaks from December to March. Some years, we can see cases still occurring in May.

Who should get a flu shot? And when?

A yearly flu vaccine is recommended for everyone 6 months and older, with rare exceptions. Getting a flu shot is especially important for people at higher risk of serious flu complications, including young children, pregnant people, adults 65 and older and people with certain chronic health conditions.

The best time to get a flu shot is September or October

Getting vaccinated in September or October gives your body time to build protection before flu starts spreading widely. It also isn’t too early, allowing it to last through the months when flu activity is usually highest.

Why flu shot timing matters

Timing your flu shot matters for these reasons:

1. Your body needs time to build antibodies. You should get vaccinated before flu begins to spread. It takes about two weeks after vaccination for the antibodies that protect you from the flu to develop in the body.

2. You want protection for the full season. If you get the shot too early, your immunity may wane before the flu season is really over.

3. If you wait too long, it may be too late. Waiting until flu is widespread before getting vaccinated may expose you to the flu virus before your body develops immunity.

Flu shot timing for children, illness and late-season protection

If you have young children aged 6 months through 8 years who are getting the flu shot for the first time – or who have only received one dose before July 1 – remember they need two doses given at least four weeks apart.

The only reason to delay getting the flu shot is because of illness. If you’re sick with a fever (not just a cold), wait until the fever has passed before getting a flu shot.

If you missed getting the flu shot in September or October, it’s not too late. Since the flu can spread well into spring, a flu shot in early November or early December – before holiday gatherings – means you’ll still reduce your risk of getting the flu in the winter and spring months.

Common flu shot side effects are usually mild

If worries about side effects of the flu shot are keeping you or your loved ones from getting vaccinated, be assured that for most people, side effects are mild.

You may notice common side effects like:

• soreness
• redness or swelling at the injection site
• headache, fever, nausea or muscle aches (less common, but may be felt by some people).

These are typically mild and go away on their own within a few days. In fact, many of these mild side effects are signs that your body's immune system is responding to the vaccine and kicking into gear to protect you from the flu.

Rare but serious side effects can occur if there is an allergic reaction. An allergic reaction would typically occur within a few hours after receiving the injection. Symptoms include breathing problems, swelling around the lips or eye, hives, weakness and a fast heartbeat. Call 911 if you suspect an allergic reaction.

If you have any questions or concerns about getting the flu shot, talk to your primary care doctor.

Can flu and other shots can be given together?

The flu shot may be given at the same time as other routine childhood or live vaccines such as MMR (measles, mumps and rubella) and varicella (chickenpox). Ask your doctor or pharmacist which vaccines are recommended for you.

Where to get a flu shot near you

Many clinics and pharmacies offer flu shot appointments.

If you are an existing patient, you can schedule online using your Allina Health account. If you have an appointment for another reason, ask for a flu shot while you’re there. If you are a new patient, call your local clinic to schedule an appointment. Find a flu shot location.