NICD issues diphtheria alert after cases rise in Western Cape

The Western Cape has seen a “marked increase” in diphtheria cases in recent weeks. Since early November, 12 respiratory diphtheria cases and 12 asymptomatic carriers who were detected during contact tracing have been identified in Cape Town, according to the National Institute for Communicable Diseases (NICD).

In Gauteng, one confirmed respiratory diphtheria patient and one asymptomatic case were identified in the second week of 2025.

Diphtheria, a contagious and potentially life-threatening disease, is caused by the pathogenic bacterium Corynebacterium diphtheriae (C. diphtheriae). The bacterial infection is vaccine-preventable.

Responding to diphtheria cases

In an alert issued on 21 January, the NICD urged clinicians throughout SA to have a “high index of suspicion” for respiratory diphtheria in patients presenting with symptoms such as a sore throat, low-grade fever and enlarged glands in the neck.

“The Western Cape Department of Health and Wellness understands the concerns of residents and assures the community that comprehensive measures are in place to address the recent cluster of diphtheria cases. We kindly urge residents to remain calm as we work diligently to safeguard public health,” said Byron la Hoe, spokesperson for the Western Cape Department of Health and Wellness.

“For every identified case, our health teams have acted swiftly, implementing public health responses to minimise the spread of infection. These include swabbing close contacts, isolating those at risk, providing preventative treatment, offering vaccinations and conducting thorough contact tracing. In affected communities, outreach activities have been conducted to raise awareness and provide support.”

The Western Cape Department of Health and Wellness provided a breakdown of laboratory-confirmed diphtheria cases by area, which included:

• Twelve cases at Pollsmoor Prison;


• Two cases in Philippi;


• Two cases in Strand;


• One case in Lotus River;


• One case in Kewtown, Athlone;


• Three cases in Chris Nissen Village, Somerset West; and


• One case each in Lwandle, Strand; Happy Valley informal settlement, Table View; Garden Village, Somerset West; and Bell Glen, Macassar.

“It is with deep sadness that we confirm the passing of a 34-year-old woman on 5 December 2024. Our thoughts and condolences are with her family and loved ones during this difficult time,” said La Hoe.

In a previous response to a Daily Maverick query from late December, La Hoe noted that the rise in diphtheria cases in the Western Cape was probably due to suboptimal vaccination coverage, especially in the six- to 12-year age group, as well as waning immunity.

Daily Maverick reached out to the National Department of Correctional Services about the management of the outbreak at Pollsmoor Prison but had not received a response by the time of publishing.

Read in Daily Maverick: Cases of rubella spike countrywide while diphtheria hits Western Cape despite being preventable by vaccination

Who is vulnerable to the disease?

Since the implementation of diphtheria immunisation in South Africa in the 1950s, there have been only sporadic cases of the disease, mostly in children aged less than 15 years, according to the NICD.

“Children who are not immunised or who did not receive or complete the Expanded Programme of Immunisation (EPI) schedule are at increased risk of getting diphtheria.

“Adults may also be at risk of contracting diphtheria if the organism is present in the community because adult immunity following vaccination wanes with time. Susceptible persons living in crowded conditions are at increased risk of getting the disease,” said the NICD.

In the first six months of 2024, there were only two cases of respiratory diphtheria reported nationally: one in KwaZulu-Natal and one in the Western Cape.

Between late July and early September of last year, a cluster of three respiratory diphtheria cases and seven asymptomatic contacts testing positive for toxigenic C. diphtheriae were identified in a community in the western subdistrict in Cape Town. Two additional cases of respiratory diphtheria were reported in the city, not linked to the cluster.

In total, 40 individuals across SA tested positive for C. diphtheriae between 1 January 2024 and 15 January 2025, 20 of whom were asymptomatic carriers detected during contact tracing.

“The median age of those with respiratory diphtheria was 22 years with a range of four to 41 years … and five of 20 (25%) individuals died,” said the NICD.

“The majority (37/40.92%) of individuals were from the Western Cape.”

Read in Daily Maverick: Covid-19 and beyond: What South Africans need to know about respiratory illnesses today

Symptoms and treatment

C. diphtheriae spreads from person to person through contact with respiratory droplets, or hand-to-mouth contact with secretions from an infected person, according to the NICD.

Symptoms include:

• A sore throat;


• Low-grade fever;


• An adherent, greyish-white membrane on the tissue of the nose, pharynx, tonsils or larynx; and


• Enlarged glands in the neck (bull neck).

“Complications of diphtheria include respiratory obstruction and myocarditis with cardiac arrest or cardiac failure,” said the NICD.

“Treatment includes antibiotics (azithromycin or penicillin) to clear the organism from the throat and prevent onward transmission, and diphtheria anti-toxin (DAT) to neutralise unbound toxin. The dosage of DAT is determined by the severity of illness and weight of the patient. Treatment should be started prior to laboratory confirmation.”

The NICD noted that early administration of DAT could be life-saving and shouldn’t be delayed in cases where suspicion of infection was high. Clinicians are expected to collect throat swabs from potential diphtheria patients and send them for diagnostic laboratory testing. DM