Diphtheria Outbreak: What You Need to Know to Protect Yourself and Your Family

Author: Gozie Oloye, LIBMS, MSc BioMedSci

Medical Reviewer: Oluwafunmike Ogwa, MBBS, MScPH

Highlights

• Diphtheria is a serious bacterial infection that can affect anyone who is unvaccinated or inadequately vaccinated.
• It spreads mainly through respiratory droplets when an infected person coughs or sneezes, or through close contact with an infected person.
• Early symptoms may include hoarseness, fever, swollen neck glands, and difficulty swallowing. A thick greyish membrane may also develop in the throat.
• Diphtheria can cause serious complications, such as heart damage and nerve issues if treatment is delayed.
• Completing the recommended vaccination schedule is advised.
• Recognising symptoms early and seeking prompt medical attention can help prevent life-threatening complications.

Introduction

When your child complains of a sore throat or develops a fever, you might think it's just another common childhood infection. But what if they are the early warning signs of an infectious disease?Diphtheria may sound like an old-fashioned disease, but its occurrence is still being reported across Nigeria. It is a serious and potentially life-threatening but vaccine-preventable bacterial infection that can affect both children and adults.

Africa is currently experiencing a diphtheria outbreak, with Nigeria reporting the highest number of cases. By August 2026, the nation reported 16,997 suspected cases, including 12,491 laboratory-confirmed infections and 596 fatalities, according to the European Center for Disease Prevention and Control (ECDC). When compared to global statistics, the outbreak's scope is very alarming. 

In 2025, the World Health Organization reported 30,205 cases of diphtheria worldwide, with Nigeria reporting 15,273 confirmed cases. Low immunisation coverage remains one of the major reasons for the diphtheria outbreak in recent years [1]. 

In this article, we'll explore what diphtheria is, the risk factors, symptoms, and when to seek urgent medical care, as well as the practical steps to take to prevent diphtheria.

What Is Diphtheria?

Diphtheria is an infectious disease caused by a bacterium (Corynebacterium diphtheriae) that produces a harmful substance and affects mainly the nose and throat and, in some cases, the skin. It can damage the cardiovascular system, kidneys, and nervous system [2]. There are 2 main ways diphtheria can affect the body:

• Respiratory diphtheria- The more serious form of diphtheria. It affects the nose and throat and can make breathing or swallowing difficult.
• Cutaneous diphtheria – This affects the skin, causing sores or wounds that may take a long time to heal.

How Does Diphtheria Spread?

The bacteria enter the body through the nose or throat and attach to the cells lining these areas. By producing harmful toxins that attach to the body's cells, it stops the cells from making the proteins they need to survive. This causes the cells to die, damaging the surrounding tissues. In severe cases, the toxin can also enter the bloodstream and affect other parts of the body, including the heart and nerves [2].

Diphtheria spreads from person to person mainly through respiratory droplets (coughs or sneezes) and close contact with infected individuals. If left untreated, transmission may persist for approximately 2 to 6 weeks. [2]. Duration varies, and appropriate antibiotics shorten the infectious period. 

Some people may not develop disease symptoms but can still transmit the bacteria to others. Someone who is infected might develop mild symptoms, although severe disease, complications, and death can also occur. Close contact with open wounds from an infected person can contribute to the spread of diphtheria.

What Are the Signs and Symptoms of Diphtheria?

Symptoms of diphtheria usually start 2 to 5 days after the organism enters the body. The following are typical diphtheria symptoms:

• Thick grey-white coating that may cover the back of your throat, nose, and tongue 
• Sore throat
• Hoarseness or change in voice
• Nasal discharge, which might be blood-stained
• Swelling in the neck, called the bull neck appearance
• Difficulty breathing and swallowing
• Mild fever and general tiredness
• Wounds that may take a long time to heal.

A thick, greyish-white covering called pseudomembrane (false tissue layer) that covers the tonsils and pharynx and may spread to other areas of the respiratory system is one of the most obvious symptoms of diphtheria. When diphtheria is first developing, this might not be apparent.

When the tissues lining the throat are harmed by the toxins generated by the diphtheria bacteria, this coating forms. This differs from regular mucus in that the membrane sticks firmly to the throat and may bleed if it is removed.

 Who Is at Risk of Diphtheria?

Anyone partially vaccinated for diphtheria or not vaccinated at all is at risk. This is because they have reduced protection against the toxin produced by the bacteria, as people who have never been vaccinated lack this vaccine-induced protection, while those who have missed doses may not have developed adequate immunity. Hence, completing the recommended doses is advised. Risk factors for infection include:

• Waning immunity against diphtheria.
• Reduced healthcare access [3]
• Lack of vaccination or incomplete immunisation, most times due to reluctance [4]
• Congested  living conditions
• Failure to receive booster doses

According to the US Centers for Disease Control and Prevention (CDC), diphtheria-containing vaccines are recommended at the following stages of life:

• Early childhood: At 12–23 months and 4–6 years.
• Adolescence: At 11–12 years.
• Adulthood: A booster dose every 10 years

How Can Diphtheria Be Prevented?

 Vaccination is the most effective way to protect against diphtheria and its serious complications. However, being vaccinated does not always prevent you from carrying or spreading the bacteria.

Other preventive measures are also important. These include:

• Practising good hand and respiratory hygiene
• Avoiding close contact with someone who has diphtheria
• Seeking prompt medical advice if you have been exposed.

 Healthcare professionals may also recommend testing, preventive antibiotics and temporary isolation to help stop the infection from spreading.The diphtheria vaccine is safe and provides immunity to diphtheria. Vaccination can help prevent symptomatic disease but does not prevent infection. There could be soreness at the injection site or a mild fever; serious reactions to the vaccine are rare. WHO recommends  3 primary doses of the diphtheria-containing vaccine during infancy, plus 3 boosters in childhood and adolescence. You will be given the diphtheria vaccine, which is given most often combined with vaccines for diseases such as tetanus, pertussis, Haemophilus influenzae, hepatitis B and inactivated polio. 

Life can get busy, and sometimes vaccination appointments get missed. You can still speak to a healthcare professional about getting your child back on track with their vaccinations if you have missed any of their appointments. Visit your nearest healthcare centre with your child's immunisation card, if available. A healthcare professional can review their vaccination history and advise you on the appropriate catch-up doses.In most cases, children do not need to restart the entire vaccination series simply because a dose was delayed or missed. A healthcare professional can assess children with unknown vaccination histories and recommend an age-appropriate catch-up schedule. If you are not vaccinated, partially vaccinated, or unsure of your status, seek advice from a designated healthcare centre to know the appropriate vaccination due.

How is Diphtheria Diagnosed?

Medical history (What your doctor or healthcare professional will ask)

The healthcare professional looking after you will ask about:

• Your symptoms (sore throat, fever, difficulty swallowing or breathing): to gain clarity on when they started
•  Your exposure: whether you have recently been in close contact with someone who has diphtheria
•  Your vaccination history: whether your diphtheria vaccination and boosters are up to date.
• Your travel history: whether you have recently visited an area where diphtheria cases have  been reported

Physical examination (what your healthcare professional will look for)

You will be examined for the following:

• A thick, greyish-white membrane covering your tonsils or throat.
• Noticeable swelling around your neck.
• Sores or wounds if cutaneous diphtheria is suspected.

Your healthcare professional will also assess how unwell you feel and if urgent treatment is needed.

Investigations (what tests your healthcare professional will carry out)

Your healthcare professional will use a sterile cotton-tipped applicator to swab the tonsils, which is sent to the laboratory for confirmation of the diphtheria toxin (C diphtheriae). Diphtheria lesions are often covered with the classic pseudomembrane. Therefore, the surface of the lesion may have to be carefully exposed before swabbing with the applicator.

Treatment of Diphtheria

If you are diagnosed with diphtheria, your treatment will usually involve immediate administration of diphtheria antitoxin and antibiotics.If your healthcare team suspects you have diphtheria, they may give you antitoxin immediately [5], even before your laboratory test results are available. This is because early treatment helps prevent the toxin from causing further damage to your body.

1. Diphtheria antitoxin: This will be given as an injection into your muscle or directly into your vein, and it helps protect the body from further harm by neutralising the toxin released by the diphtheria bacteria. However, it can only stop toxins that are not attached to your body's cells yet. 
2. Antibiotics: Receiving antibiotics promptly helps clear the bacteria from your body and reduces the risk of spreading the infection to others.

What Should You Do If You Suspect Diphtheria?

Seek medical assessment immediately if you have travelled to a country where diphtheria is found, and you develop some symptoms within 2-5 days of exposure, and you suspect diphtheria, or if you have been in close contact with someone who has diphtheria.Contact your nearest healthcare facility before arriving so staff can take precautions because diphtheria spreads easily. 

Complications of Diphtheria

These include:

1. Cardiac Complications

Myocarditis, which is inflammation of the heart muscle, can accompany diphtheria. [2]

2. Neurologic Complications

This can include nerve weakness or paralysis, particularly involving the peripheral nerves, leading to extreme muscle weakness. 

3. Airway Obstruction
4. Kidney damage (Nephritis) [6]
5. Death

When to Seek Medical Emergency

Seek emergency help if you have any of the following:

1. Breathing problems
2. Difficulty swallowing
3. Neck swelling
4. Extreme weakness, or signs of heart problems

.Don’t wait at home until breathing becomes difficult. 

How to Manage Diphtheria after Recovery

Patients may need follow-up visits and testing to verify that the infection has cleared. A vaccination assessment is needed to ensure their vaccination record is updated because a previous infection does not automatically guarantee immunity to further infections.

Conclusion

Diphtheria is a serious infection, but vaccination largely prevents it. Checking that you and your child's vaccinations are up to date and spotting early signs and symptoms are essential.Don't dismiss what may look like an ordinary sore throat or fever. It could be more serious than you think.

Frequently Asked Questions (FAQs)

1. Can someone who has been vaccinated still get diphtheria?

Yes. Although vaccination greatly reduces the risk of severe illness, it does not provide complete protection against infection. Completing the recommended vaccine doses and receiving boosters are important.

2. Is diphtheria contagious, and how does it spread?

Yes, diphtheria is contagious. It spreads mainly through respiratory droplets released when an infected person coughs or sneezes. Someone carrying the bacteria may spread the infection even without showing obvious symptoms.

3. Can diphtheria be treated?

Yes. Diphtheria can be treated. Treatment usually involves diphtheria antitoxin to destroy circulating toxin and antibiotics to clear the bacteria. 

4. Where can I get my child vaccinated against diphtheria?

Parents and guardians can visit their nearest primary healthcare centre, and any missed doses (if any) can be completed. 

References

1. Adegboye OA, Alele FO, Pak A, et al. A resurgence and re-emergence of diphtheria in Nigeria, 2023. Therapeutic Advances in Infectious Disease. 2023;10. Available from: https://journals.sagepub.com/doi/10.1177/20499361231161936

2. Vijayan V, Radhakrishnan S. Diphtheria. [Updated 2026 Jul 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560911/

3. Truelove SA, Keegan LT, Moss WJ, Chaisson LH, Macher E, Azman AS, Lessler J. Clinical and Epidemiological Aspects of Diphtheria: A Systematic Review and Pooled Analysis. Clin Infect Dis. 2020 Jun 24;71(1):89-97. doi: 10.1093/cid/ciz808. PMID: 31425581; PMCID: PMC7312233. Available from: https://pubmed.ncbi.nlm.nih.gov/31425581/

4. Gulumbe BH, Danlami MB, Yusuf AB, Shehu A, Chidiebere O. Vaccine hesitancy under the lens: Nigeria’s struggle against the worst diphtheria outbreak in decades. Therapeutic Advances in Infectious Disease. 2024;11. Available from: https://journals.sagepub.com/doi/10.1177/20499361241242218

5. Marshall C, Caro WP, Costa A, Ho LL, Gardner PJ, Guitton C, Potet J, Sparrow E. Diphtheria Antitoxin Production and Procurement Practices and Challenges. Emerg Infect Dis. 2025 Dec;31(12):1-7.  PMID: 41491021; PMCID: PMC12782264. Available from: https://wwwnc.cdc.gov/eid/article/31/12/25-0796_article

6. Ahmed AA, Omar NMS, Abdi AE, Ali IH, Ahmed FA. A complex case of diphtheria in a pediatric patient: complications of renal failure and myocarditis. Int J Emerg Med. 2026 Feb 24;19(1):53. doi: 10.1186/s12245-026-01146-9. PMID: 41735838; PMCID: PMC12933985. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC12933985/

Disclaimer:
The information provided on this website is for general educational and informational purposes only. It is not intended to replace professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

Published October 27, 2026