What should you know about diphtheria vaccine?

Diphtheria is a bacterial infection that can form a thick coating in the throat and release a toxin affecting other organs. Vaccination prepares immune defences before exposure; it does not treat an existing infection. The vaccine is commonly combined with protection against tetanus and pertussis, so the product name may contain several letters.

Check the person’s immunisation record and arrange the recommended dose with a licensed clinician. Tell the vaccinator about a previous severe reaction, current illness, pregnancy, or medicines that affect immunity. Mild soreness, redness, or a short-lived fever can occur after an injection. Keep the record updated and follow the schedule offered by your local health service. See [Childhood Immunisation](/treatments/preventive-care-and-vaccination/childhood-immunisation/) for related routine protection.

Get emergency help for trouble breathing, inability to swallow, bluish lips, rapidly worsening throat swelling, faintness, or widespread swelling soon after vaccination. A severe allergic reaction needs immediate treatment. If fever or pain is persistent, or a sore throat is worsening after possible exposure, contact a clinician promptly; [Sore Throat](/symptoms/sore-throat/) explains symptoms that may need assessment.

Ask which vaccine formulation is planned, whether any doses are missing, and what timing fits the person’s age and history. You can also ask what to do after a delayed dose and which symptoms should prompt a call.