Diphtheria is a bacterial infection commonly affecting the nose and throat. It is characterised by a thick, grey matter covering the back of the throat.

Diphtheria is indicated by the following symptoms:
- A thick, grey matter covering the back of the throat
- Dyspnoea
- Hoarseness of voice
- Enlarged lymph nodes
- Sore throat
- Fever with chills
- Dysphagia or slurred speech

Diphtheria is diagnosed by the following methods:
- Examination of signs/symptoms
- Physical examination
- Throat culture
- Wound culture

Diphtheria is commonly spread by:
- Sharing household items
- Airborne respiratory droplets (coughing/sneezing)
- Close contact with infected persons

The vaccine against Corynebacterium diphtheriae (the primary causal agent for diphtheria) is available. It is given in combination with other vaccines such as tetanus and pertussis vaccine. The first dose is commonly administered at six weeks after birth. Two additional doses at a gap of four weeks are usually administered after the main dose. Booster doses are further administered with time.