A- A A+
Home > Patients and Visitors > Health Library

Influenza Vaccine

​What is Influenza?

Influenza, commonly known as the flu, is a common infection that is spread mainly by coughing, sneezing, and close contact. 

The symptoms include fever, cough, sore throat, body aches and tiredness.

In high-risk persons, influenza can cause more severe illness, resulting in hospital admissions and even death.

Why Should I go for Influenza Vaccine?

Influenza infection is a risk even in tropical countries.

In Singapore, there are two seasonal peaks for influenza every year.

  • November to January
  • May to July

Annually, 12% of pneumonia and influenza hospitalisations and 600 deaths arAe estimated to be caused by influenza in Singapore.

Influenza vaccine reduces the risk of infection caused by influenza viruses. You should get vaccinated while you are well to protect yourself from influenza and its complications.

Who Should Receive the Influenza Vaccine?

People who are at high risk for developing influenza complications should go for the vaccination. People at high risk include:

  • Older adults aged 65 years and above
  • Pregnant women in any trimester
  • Persons with medical conditions such as diabetes, heart, lung, liver and kidney disease
  • Persons with conditions that lower the body's resistance to infection (e.g. leukemia, HIV, spleen removed, or organ transplant)
  • Persons on medications or treatments that lower the body's resistance to infection (e.g. long term steroids, certain cancer drugs, radiation therapy)

When Should I Receive my Influenza Vaccine?

You should take your influenza vaccination every year as flu viruses are constantly changing and your body's immunity to influenza viruses may decrease over time.

In some years, health authorities may recommend vaccination earlier than 12 months because the vaccine has been updated to match changes in the influenza virus.

If it has been more than 12 months since your last flu vaccination, do remind your doctor that you need a flu vaccine every year.

Where can I get my Vaccine?

You can get your vaccination at all polyclinics and hospitals.

Medisave may be used for people who are at high risk of developing influenza complications.

What can I Expect After the Vaccine?

You may experience the following 1 to 2 days after the vaccination:

  • Soreness, redness, or swelling where the injection was given, slight headache, body aches or tiredness. This usually gets better on its own within 2-3 days.
  • Fever (temperature above 38⁰C) is uncommon and usually gets better in 1-2 days.  

Paracetamol (1-2 tablets every 6 hours as needed) may help reduce any discomfort. Do not exceed 8 tablets (500mg per tablet) in a day.

What are the Risks and Complications of the Vaccine?

Vaccines, like any medicine, can have side effects. The side effects may vary from mild to severe adverse reactions and vary between individuals.

Mild side effects include:

  • Pain or swelling where the injection was given.
  • People taking blood thinners (e.g. warfarin) or with bleeding problems may develop a hematoma (small lump with blood) where the injection was given but this is uncommon.
  • Some people may feel faint after the vaccination. Sit for 15 minutes to avoid fainting and any subsequent injuries.

Serious reactions are possible but extremely rare.

  • Severe allergic reactions (anaphylaxis) can occur for 1 in a million doses and can happen within minutes to a few hours after vaccination.
  • The risk of getting Guillain-Barré Syndrome (GBS), a rare nerve condition, is estimated at 1 or 2 cases per million vaccinations.

Overall, these risks are much lower than the risk of severe complications from influenza infection, which is what we hope to prevent by providing vaccination.

As with any medicine, there is a very remote chance of a vaccine causing serious injury or death. However, health authorities in Singapore and around the world recommend vaccination because the benefits are greater than the possible risks.

What Should I do if There is a Serious Reaction to the Vaccine?

Please let the nurse or doctor know immediately, or call an ambulance to go to hospital immediately, if you experience any of the following:

  • Hives
  • Face or throat swelling
  • Difficulty breathing
  • Dizziness

Where can I Learn More About Influenza Vaccine?

For more information on influenza and influenza vaccination, visit HealtHub or Communicable Diseases Centre (CDC) page.

Last Updated on