Everything you need to know about the Flu Vaccine and Its Side Effects

A simple vaccine is the best way to protect yourself from the flu. It may sound like a minor illness, but it can cause enormous problems for some people and even be deadly.

When should I get it?

The best time to get a flu shot is as soon as it’s available. It takes about two weeks for the vaccine to be effective, so the earlier you get it, the higher your odds of staying well.

What types of vaccine can I get?

There are several:

  • The traditional flu shot is an injection into your arm muscle. It’s made from pieces of inactive flu viruses.
  • An egg-free flu shot is an option for people over the age of 18 who have severe egg allergies.
  • The high-dose flu shot is for people aged 65 and older. They may need a stronger dose to get the same protection.
  • An intradermal flu shot uses a tiny needle that only goes skin deep. It’s for people aged 18 to 64.

Some vaccines protect against more than one flu virus strain. Trivalent vaccines work against three strains and quadrivalent vaccines fight four types of flu. The traditional flu shot comes in both forms and the high-dose only in the trivalent form.

How does it work?

The shots prompt your body to get ready to fight an infection from the flu virus. It helps you create tools, called antibodies, to fight the virus when you’re exposed to it. Doctors tweak the vaccines each season and select strains based on the ones they think are most likely to show up that year.

The vaccine itself doesn’t cause the flu but it takes about two weeks to start working. Some people get it, then catch the virus before their body is ready to fight it. It’s human nature to see a link between the two events, but the flu shot can’t cause the flu or make you more likely to get it. You can also get sick even if you get the vaccine, but your illness will most likely be milder.

Who should get it?

We recommend that everyone 6 months and older get immunised against the flu unless there’s a medical reason not to. The vaccine is especially important for people who are at high risk of serious complications if they get the flu, including:

  • Kids younger than 5, but in particular those under the age of 2.
  • The elderly – 65 or older.
  • Pregnant women.
  • People who live in nursing homes or long-term care facilities.
  • Adults and kids with diseases of the lungs (like asthma), heart, kidneys, liver, blood, or metabolism (like diabetes).
  • Anyone under the age of 19 who gets long-term aspirin therapy.

Should I talk to my Doctor first?

Ask your doctor first if:

  • You’ve had an allergic reaction to a flu shot in the past.
  • You’re very ill. If you have a mild illness, it’s usually okay to get vaccinated, but talk to your doctor first.

What are the side effects?

You might have a mild fever and feel tired or achy after you get the shot. Some people also have soreness, redness, or swelling where the needle went in. These problems aren’t serious and won’t last long.

Serious side effects are rare. If you do get them, it should be within a few minutes to a few hours after you get the shot. Get emergency help right away if you have trouble breathing, hives, feel weak or dizzy, or have a fast heartbeat after you get it.

Side effects in children can include:

  • Runny nose
  • Headache
  • Vomiting
  • Muscle aches
  • Fever

Side effects in adults can include:

  • Runny nose
  • Headache
  • Sore throat