If you feel any of these side effects, rest and take paracetamol.
Serious side effects:
Serious side effects such as a severe allergic reaction are rare.
In very rare cases Guillain-Barré syndrome (GBS) has been reported. GBS is a condition that affects the nerves in the body. It causes nerve inflammation and can cause pain, numbness, muscle weakness and difficulty walking. You are far more likely to get Guillain-Barré syndrome from having the flu than from the flu vaccine.
Protection from the flu
Most people who get the vaccine will be protected from the flu. You can still get the flu after vaccination. But you should have milder symptoms and recover faster.
We do not know yet how effective this year's vaccines are. But normally the vaccine reduces the risk of getting flu by 40% to 60%. You need to have the flu vaccine every year. This is because the antibodies that protect you fade over time. Flu strains also change each year.
Flu vaccine and other vaccines
If you have had other vaccines recently, it is safe to get the flu vaccine.
For example, if you have had your:
• COVID-19 vaccine, booster shot or additional dose
• pneumococcal vaccine (pneumonia vaccine) - if you are 65 or older this is recommended
• school vaccines
Who should not get the flu vaccine
You should not get the flu vaccine if you:
• have had a severe allergic reaction to a previous flu vaccine or any part of the vaccine (including polysorbate-80)
• are taking medicines called combination checkpoint inhibitors, for example, ipilimumab plus nivolumab
• have a temperature greater than 38 degrees Celsius - wait until you are well before getting the vaccine
• have severe neutropoenia - low levels of a type of white blood cell
• if you have primary autoimmune neutropenia, you should be able to get the flu vaccine. Talk to your GP if you are not sure.