Flu shot: What are the possible reactions and side effects?

Fact Checked

Generally, many children can tolerate a flu shot well and other factors are inappropriately blamed on the reactions that occur. There are reports in which some individuals claim to get the flu every time a flu shot is given which is not possible since the shot is not a live vaccine.

The nasal form of the flu vaccine is created using the live vaccine but it is made from weakened viruses and could not trigger the condition.

Possible side effects of a flu shot

Even though a flu shot will not trigger the flu, receiving a flu shot can typically trigger mild side effects particularly among younger children who are given the shots for the first time. The serious reactions are considered uncommon. The usual side effects that can occur after a shot is given includes the following:

  • Localized reactions to the flu shots includes pain, swelling and soreness in the site of injection but are usually mild and only lasts for less than 2 days.
  • Systemic reactions typically start 6-12 hours after a flu shot is given and lasts for 1-2 days which includes rash, fever, malaise and muscle aches.
  • Allergic reactions include angioedema, hives and anaphylaxis which can be life-threatening but considered rare and instigated by the residual egg proteins among those who are allergic to other components in a flu shot.
    Flu shot
    Among children who were given the initial flu shot, fever and fussiness can occur right away which is a usual side effect.

Even though there is a minimal risk for Guillain-Barre Syndrome (GBS) after receiving a flu shot, the risk is small. A shot is believed to be linked with febrile seizures in some young children particularly if given with other vaccines.

Reactions to a flu shot

Among children who were given the initial flu shot, fever and fussiness can occur right away which is a usual side effect. Luckily, this typically lasts for 1-2 days and the child should start to feel better.

Since this is quite common during the initial time the flu shot is given, there is no need to expect the same side effects when a flu shot is given next year or with the second shot.

Even if the fever is a likely reaction after a flu shot, a doctor should be consulted especially if it is hard to control, the child appears fussy or inconsolable or his/her condition does not get any better. In case the child has a serious reaction to a flu shot, a doctor should be consulted first before receiving a shot in the future.

Reactions to the nasal spray flu vaccine

An alternative to a flu shot is the nasal spray flu vaccine. The possible reactions of this form of flu vaccine include the following:

  • Low grade fever
  • Runny nose or nasal congestion
  • Headache
  • Muscle aches
  • Sore throat

The other reactions that can manifest after the nasal form is used might include weakness, sore throat, chills, cough and sinusitis.

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