Flu shot after flu: what to know

Having flu gives your immune system experience with the virus that caused that illness, but influenza viruses vary. A later infection may involve a different strain, and immunity can change over time. The vaccine is designed for the strains expected to circulate during the relevant flu season, so a previous illness does not automatically make vaccination unnecessary.

A flu shot does not treat an infection that is already under way and cannot remove ongoing fever, cough, or tiredness. Recovery can take time, especially after a more intense illness.

Wait until you are feeling well enough to attend and tell the vaccinator when your flu symptoms started and whether you still have a fever. They can consider your current health, previous vaccine reactions, and the product available. If you are still acutely unwell, ask when vaccination should be rearranged.

Rest, drink fluids, and follow the advice given for your recovery. A sore arm or mild, short-lived feeling of unwellness can occur after vaccination. Read about the [Inactivated Vaccine](/materials/inactivated-vaccine/) to understand the type of product commonly used.

Seek urgent care for trouble breathing, chest pain, new confusion, fainting, severe weakness, or difficulty staying awake. Contact a clinician promptly if fever returns after improving, symptoms are worsening rather than settling, or you cannot keep fluids down. These warning signs need assessment regardless of whether you have received a flu shot.

Ask: Is vaccination useful for me after this illness? Should I wait until my symptoms have settled? Which vaccine is suitable with my medical history? Could my current medicines or another recent vaccine affect the timing?