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Influenza Vaccine

Vaccination Information Leaflet
  • Article last reviewed 22 May 2026
  • 5 mins read

What Is the Influenza Vaccine Used For?

Influenza vaccines help to prevent influenza (also known as flu), a common infection caused by Influenza virus types A and B.

It takes at least 2 weeks for protection to develop after vaccination.

Flu symptoms include fever, chills, headache, feeling tired, muscle aches, sore throat and cough.

Who Should Receive the Influenza Vaccine?

According to the National Adult Immunisation Schedule (NAIS) and National Childhood Immunisation Schedule (NCIS) The flu jab or flu shot is recommended for everyone and especially in people who are at high risk of developing influenza complications such as:

Elderly aged 65 years and older

Pregnant women in any trimester

Persons with chronic medical conditions such as diabetes or heart, lung, liver and kidney disease

Persons with lower body resistance to infections due to :

Conditions such as leukaemia, HIV, spleen removal, or organ transplant

Using medications or receiving treatment such as taking long-term steroids, certain cancer drugs or radiation therapy

Residents staying in intermediate or long-term care facilities

Persons aged 18 years or younger and receiving long-term aspirin therapy

Children aged 6 months old to 59 months

Click here to book a flu vaccination appointment.

What Precautions Should I Follow Before Receiving the Influenza Vaccination?

Inform your healthcare professional if:

You are allergic to this vaccine or any of the other ingredients of this vaccine

You have a history of Guillain-Barré Syndrome (a rare condition where the body’s immune system attacks the nerves)

You have a severe allergy to eggs

How Is the Influenza Vaccination Given?

The flu vaccine or flu shot is either given by injection into a muscle or just underneath the skin.

One dose is recommended per year as flu viruses are constantly changing, and your body’s immunity to influenza viruses may decrease over time.

What Are Some Side-Effects That I Need to Seek Medical Advice Immediately?

Severe allergic reactions (anaphylaxis) are rare and can happen within minutes to a few hours after vaccination.

The symptoms of a severe allergic reaction include one or more of the following:

Swollen face/eyes/lips/tongue

Difficulty in breathing

Itchy skin rashes over your whole body

If you experience any of these symptoms, you should inform your healthcare professional immediately.

What Are Some Other Side-Effects of the Influenza Vaccine?

Some people may feel faint after the vaccination

Sit for 15 minutes after receiving the vaccine to avoid fainting

Soreness, redness, or swelling at the injection site, slight headache, body aches or tiredness, fever

These side effects usually go away on its own within 2 to 3 days

You may take paracetamol to help to relieve the pain or fever

Disclaimer

The content of this article does not replace the information from your healthcare professional. Please consult your healthcare professional for more information. 

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (NHG Health, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore (PSS). 

The images and video in this article has been developed by the Singapore National Asthma Programme (SNAP) and have been reviewed by the PSS-National Medication Information workgroup.