Diphtheria virus: what it is and how to respond

Diphtheria is caused by toxin-producing bacteria rather than a diphtheria virus, and vaccination is the main preventive measure. The toxin can injure tissues in the throat and elsewhere, so suspected illness needs prompt clinical assessment.

The bacteria can colonise the nose or throat and spread through respiratory droplets or close contact with secretions. Some infections produce a thick coating in the throat, while toxin effects can affect breathing and other organs. A sore throat alone has many possible causes and does not identify diphtheria; a clinician may need examination and testing to distinguish them.

Seek medical advice promptly and mention possible exposure, vaccination history and symptoms. Avoid close contact until a clinician gives guidance, and do not share cups or utensils. Antibiotic Treatment may be used when a bacterial infection is diagnosed, while vaccination protects against future disease. Childhood Immunisation explains routine prevention.

Get emergency help for noisy or difficult breathing, inability to swallow saliva, bluish lips, collapse or rapidly worsening throat swelling. Prompt assessment is also needed for a sore throat with marked weakness or a visible throat coating. More general symptom information is available under Sore Throat.

Ask whether testing, isolation advice or treatment is needed, whether close contacts should be assessed, and whether your vaccination record is complete. Tell the clinician when symptoms began and whether breathing or swallowing has changed.