Health Topic

Diphtheria

Diphtheria is a bacterial infection spread through contact with an infected person or object. Diphtheria usually affects the nose and throat.

Reviewed Reviewed by a registered pharmacistGeneral information

Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About Diphtheria

Diphtheria is a serious bacterial infection. You can catch it from a person who has the infection and coughs or sneezes. You can also get infected by coming in contact with an object, such as a toy, that has bacteria on it.

Diphtheria usually affects the nose and throat. Symptoms include:

  • Sore throat
  • Swollen glands in the neck
  • Fever
  • Weakness

Your doctor will diagnose it based on your signs and symptoms and a lab test. Getting treatment for diphtheria quickly is important. If your doctor suspects that you have it, you'll start treatment before the lab tests come back. Treatment is with antibiotics.

The diphtheria, pertussis, and tetanus vaccine can prevent diphtheria, but its protection does not last forever. Children need another dose, or booster, at about age 12. Then, as adults, they should get a booster every 10 years. Diphtheria is very rare in the United States because of the vaccine.

Centers for Disease Control and Prevention

It sits within Infections and Ear, Nose and Throat.

The lead U.S. institute for this subject is the National Institute of Allergy and Infectious Diseases.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Diphtheria

358 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

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Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Diphtheria. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Diphtheria, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.