As with any medications, vaccines can have side effects. The most common side effects following influenza vaccination include mild fever, headache, muscle and joint pain, and injection site reactions. These can occur in the first three days after vaccination and can generally be managed safely at home. Talk with your immunisation provider about what to expect.
Serious side effects are rare. In Australia, we have AusVaxSafety, which monitors the safety of vaccines including seasonal influenza vaccines. This system uses a short SMS survey to ask patients, or parents of children, in a large number of general practices around Australia, if they experienced any health issues in the first few days after vaccination. In 2019, 93.9% of people that participated in the survey reported no adverse events following immunisation. Of the 6.1% of people that reported an adverse event, the majority were generally mild and short-lived. You can visit AusVaxSafety for further information.