What should you know about diphtheria vaccine for what?

Diphtheria bacteria can settle in the throat and produce a toxin. That toxin may damage breathing passages and other parts of the body. The vaccine teaches the immune system to respond to the toxin before exposure. It is preventive, so it cannot clear an infection already under way and does not replace assessment of a concerning illness. Protection is often delivered in a combination vaccine.

Review the person’s immunisation history with a healthcare professional and follow the schedule recommended for age and circumstances. Tell the clinician about allergies, immune-suppressing treatment, pregnancy, or a previous vaccine reaction. Keep documentation after each appointment. If infection is suspected, avoid close contact while seeking medical advice; [Antibiotic Treatment](/treatments/medical-management/antibiotic-treatment/) may be relevant to treatment decisions, but antibiotics are not a substitute for vaccination.

Seek emergency care for difficulty breathing, inability to swallow saliva, noisy breathing, severe weakness, or swelling of the face or throat. These signs can worsen quickly and should not be judged by vaccination status. A persistent or severe sore throat, especially after known exposure, warrants prompt clinical advice; read [Sore Throat](/symptoms/sore-throat/) for warning symptoms.

Ask what the vaccine covers, which dose is appropriate, whether any boosters are due, and how to interpret a past reaction. Ask where to seek help if a household contact develops throat symptoms.