What should you know about flu shot protection?

Protection depends on how closely the vaccine matches influenza viruses circulating at the time and on your age, health, and immune response. You may still catch flu or another respiratory infection after vaccination. If illness occurs, vaccination can make the illness less severe and reduce the chance of complications. The injected inactivated vaccine cannot give you influenza because it does not contain a live, infection-causing virus.

Arrange vaccination through a licensed healthcare provider and tell them about previous vaccine reactions, allergies, pregnancy, or a weakened immune system. Continue hand hygiene, ventilation, and staying home when unwell, since vaccination does not stop every respiratory infection. If you develop flu-like symptoms, rest, drink fluids, and ask promptly about treatment when you have a long-term condition or are at higher risk of severe illness.

Seek urgent medical help for trouble breathing, swelling of the lips or throat, widespread hives, fainting, confusion, or severe weakness after vaccination or during an illness. Contact a clinician if fever or respiratory symptoms are worsening, you cannot keep fluids down, or an existing medical condition is becoming harder to control.

Ask whether this vaccine is suitable for you, when protection is expected to build, and which symptoms should prompt urgent assessment. You can also ask how vaccination fits with your regular medicines and any other vaccines you need.