Diphtheria, a vaccine-preventable bacterial infection that attacks the throat and can cause life-threatening complications, has resurfaced in South Africa with 32 confirmed cases identified between December 2025 and June 2026. The outbreak, concentrated primarily in the Western Cape region, serves as a stark reminder that diseases once thought conquered can return when vaccination rates decline. Understanding the symptoms and seeking immediate medical care is critical, as early treatment can be lifesaving.

What Is Diphtheria and How Does It Spread?

Diphtheria is caused by a bacterium called Corynebacterium diphtheriae and spreads through respiratory droplets when an infected person coughs or sneezes. The disease primarily affects the throat and can also involve the nose and larynx, the voice box. What makes diphtheria particularly dangerous is that it produces a toxin that can damage the heart, nerves, and kidneys, even after the initial infection is treated.

The current outbreak in South Africa has identified not only confirmed cases but also probable cases and asymptomatic carriers. Between the last two weekly reports in June 2026, two new laboratory-confirmed cases emerged from Limpopo province, along with five probable cases, two of which were fatal. The majority of confirmed cases, 91 percent or 29 out of 32 total, have occurred in the Western Cape, with smaller clusters in Limpopo and Gauteng provinces.

What Are the Warning Signs of Diphtheria?

Recognizing diphtheria early is essential because prompt treatment can prevent severe complications. The disease typically begins with symptoms that might seem like a common sore throat but progress in distinctive ways. If you or a family member experiences these signs, seek medical attention immediately, especially if vaccination status is unknown or incomplete.

• Sore Throat: The infection starts with throat pain, often accompanied by a low-grade fever that may not be dramatically high.
• Distinctive Membrane: A greyish-white membrane forms and firmly adheres to the tissue of the nose, pharynx (throat), tonsils, or larynx. This membrane is a hallmark sign that distinguishes diphtheria from other throat infections.
• Neck Swelling: Enlarged glands in the neck develop, sometimes creating a swollen appearance referred to as "bull neck" due to the pronounced swelling.
• Systemic Complications: In severe cases, the toxin produced by the bacteria can cause heart inflammation, nerve damage, and kidney problems that may develop days or weeks after the initial infection.

How Is Diphtheria Treated?

Treatment must begin immediately upon suspicion of diphtheria, even before laboratory confirmation is complete. Delaying treatment while waiting for test results can allow the toxin to cause irreversible damage. The treatment approach combines two critical components to address both the infection and its toxic effects.

Antibiotics, specifically azithromycin or penicillin, are administered to eliminate the bacteria from the throat and prevent the infected person from spreading the disease to others. Simultaneously, diphtheria antitoxin (DAT) is given to neutralize any toxin that has already been released into the bloodstream. The dosage of antitoxin depends on how long the person has been ill and how severe their symptoms are. Supportive care focuses on protecting the airway, which may include oxygen therapy, heart monitoring, and in severe cases, intubation or a surgical airway procedure called a tracheostomy.

Why Is Vaccination the Best Defense?

Diphtheria is entirely preventable through vaccination, yet the resurgence in South Africa highlights gaps in immunization coverage. The disease can occur in people of all ages, but vaccination rates determine whether outbreaks spread or remain contained. Public health authorities have initiated appropriate responses for all suspected and confirmed cases, including contact tracing and chemoprophylaxis, which is preventive antibiotic treatment given to people who have been exposed.

The fact that asymptomatic carriers have been identified in the outbreak underscores another critical point: people can harbor and transmit the bacteria without showing symptoms themselves. This makes vaccination not only a personal health decision but a community responsibility. If you are unsure of your vaccination status or that of your children, consulting with a healthcare provider about the diphtheria-tetanus-pertussis (DTP) vaccine is an important step in protection.

Steps to Protect Yourself and Your Family

• Verify Vaccination Status: Check your immunization records and those of your family members to confirm you have received the complete diphtheria vaccination series and any recommended boosters.
• Seek Immediate Care for Symptoms: If you develop a sore throat with a distinctive membrane, fever, or neck swelling, contact a healthcare provider right away and mention the possibility of diphtheria.
• Practice Respiratory Hygiene: Cover your mouth and nose when coughing or sneezing, wash your hands frequently, and avoid close contact with people who have respiratory infections.
• Stay Informed About Local Outbreaks: Monitor public health announcements in your region, particularly if you live in or travel to areas with confirmed diphtheria cases.

The South African diphtheria outbreak serves as a timely reminder that vaccine-preventable diseases remain a threat when immunity levels drop. With prompt recognition, immediate medical treatment, and widespread vaccination, diphtheria can be controlled and eventually eliminated. If you have any concerns about your health or vaccination status, speaking with a healthcare provider is the best course of action.