What should you know about seasonal influenza vaccine?

Influenza changes over time, so the vaccine is updated for the season and protection can lessen as months pass. An inactivated vaccine contains virus material that cannot cause influenza. Your immune system uses that material to build a response, but vaccination does not treat an infection that has already started.

You may have a sore arm, mild tiredness, or a low fever for a short time after vaccination. These effects are generally milder than influenza itself. Tell the clinician about previous vaccine reactions, severe allergies, pregnancy, or a weakened immune system so they can check which option is suitable.

Arrange vaccination before influenza begins circulating widely, following the schedule advised by your healthcare professional. You can read about the [Inactivated Vaccine](/materials/inactivated-vaccine/) as one vaccine material. Continue hand hygiene, ventilation, and staying home when unwell because vaccination does not prevent every respiratory infection.

If you develop fever, cough, or body aches after vaccination, contact a clinician for advice rather than assuming the symptoms are caused by the injection. Keep a record of the date and product received for future appointments.

Seek urgent medical help for trouble breathing, swelling of the face or throat, fainting, confusion, blue lips, or rapidly worsening illness after vaccination or during a suspected influenza infection. A severe allergic reaction can begin soon after an injection, while breathing problems from infection need prompt assessment.

Ask whether vaccination is recommended for you this season, which product fits your age and health history, what to do if you are currently unwell, and when you should receive another dose.