Key facts
- Since the beginning of 2026, and as of October 2026, diphtheria outbreaks have been reported in nine African countries, with considerable variation in reported case numbers, epidemiological trends and geographical distribution.
- In 2026, as of October 2026, Nigeria reported the highest number of cases, followed by Chad. Reported case numbers declined substantially in Mali but increased in Guinea. Transmission remained geographically widespread in Mali, Mauritania, Niger and Nigeria, while South Africa reported localised clusters and sporadic cases. A recent outbreak in Senegal and localised clusters in Morocco were also reported.
- Most EU/EEA countries have very high vaccination coverage for the primary course of diphtheria-containing vaccines. In countries with high vaccination coverage, the risk to the general population is assessed as very low. Travellers to the regions with active case transmission should ensure they are up to date with vaccinations.
- ECDC monitors diphtheria events worldwide, including in Africa and the EU/EEA, through routine epidemic intelligence activities and disease network surveillance.
Overview
Epidemiological overview
Between 2000 and 2025, a total of 96 036 diphtheria cases have been reported in nine countries of the WHO African Region (WHO), including Algeria, Chad, Gabon, Guinea, Mali, Mauritania, Niger, Nigeria and South Africa (WHO RRA v.1). Since the beginning of 2026, and as of September 2026, persistent transmission of diphtheria has continued in Chad, Guinea, Mali, Mauritania, Niger, Nigeria and South Africa (WHO RRA v.3). Senegal reported a new outbreak in July-August 2026 (WHO RRA v.3) and localised clusters were detected in Morocco in September 2026 (Morocco World News).
Reported case numbers, geographical distribution and epidemiological trends varied considerably across countries. An overview of the epidemiological situation of diphtheria in the WHO African Region is provided below, drawing on publicly available official sources from the World Health Organization (WHO) and national epidemiological reports, and media.
Chad: Between 1 January and 26 July 2026, 1 251 suspected cases, including eight laboratory-confirmed cases and five deaths (Case Fatality Ratio [CFR]: 0.4%) were reported across four of 23 provinces. Chad reported the second highest number of suspected cases in the WHO African Region, after Nigeria. Reported case numbers remained relatively stable during 2026 (WHO RRA v.3).
Guinea: As of epidemiological week 33, 600 suspected cases were reported, including 49 laboratory-confirmed cases and 89 deaths (CFR: 14.8%). This represented an additional 463 cases and 78 deaths since 1 March 2026. Laboratory-confirmed cases were reported in Siguiri, Kankan, Mandiana and Mamou prefectures. During week 31, 34 suspected cases, including 17 laboratory-confirmed cases and eight deaths, were reported. All deaths occurred in unvaccinated children aged 12 months to 14 years, and 72% of cases were children older than 5 years (WHO RRA v.3). Between 1 January 2025 and 22 February 2026, a total of 795 suspected cases, including 151 deaths (CFR: 19%) had been reported (WHO RRA v.2).
Mali: As of epidemiological week 33, 192 suspected cases, including 30 confirmed cases and nine deaths (CFR: 4.7%) were reported. Suspected cases were reported from 41 health districts in nine regions (increasing from 37 health districts up until 1 March 2026), and confirmed cases were reported from 25 health districts in eight regions (WHO RRA v.3). From 1 January 2025 to 1 March 2026, a total of 636 suspected cases had been reported, including 35 deaths (CFR: 5.5%) (WHO RRA v.2). Reported case numbers declined in 2026 following a peak recorded in week 19 of 2025. Children aged 5-14 years remained the most affected age group (WHO RRA v.3).
Mauritania: As of epidemiological week 33, Mauritania reported 448 suspected cases, including 19 laboratory-confirmed cases and 25 deaths (CFR: 5.6%). Cases were reported across 36 of 63 moughataas (health districts) (increasing from 34 affected moughataas up until 1 March 2026), with the largest number reported in the Hodh El Chargui region (WHO RRA v.3). From 1 January 2025 to 1 March 2026, a total of 1 415 suspected cases, including 12 laboratory-confirmed cases and 54 deaths (CFR: 3.8%), had been reported (WHO RRA v.2). A substantial increase in weekly case numbers was recorded between weeks 39 and 44 of 2025, reaching a peak of 179 cases in week 41, before declining in 2026 (WHO RRA v.2, WHO RRA v.3).
Morocco: On 28 September 2026, according to media sources quoting the Ministry of Health and Social Protection of Morocco, two family clusters of diphtheria were reported in the Souss-Massa region. One case was laboratory-confirmed and eight cases, including two deaths, were suspected. Further laboratory investigations were ongoing at the time of reporting (Morocco World News, The North Africa Post).
Niger: As of epidemiological week 33, 818 suspected cases, including 313 laboratory-confirmed cases and 27 deaths (CFR: 3.3%), were reported across 45 of 72 health districts. This represented an increase of 543 suspected cases and 12 deaths since 1 March 2026. The number of affected areas also increased from 34 health districts up until 1 March 2026 (WHO RRA v.3). From 1 January 2025 to 1 March 2026, a total of 2 456 suspected cases, including 166 deaths (CFR: 6.8%), had been reported (WHO RRA v.2). Following an increase during the first six weeks of 2026, weekly case numbers generally declined, although fluctuations continued. Reported case and deaths counts, as well as the CFR, were lower than during the corresponding period in 2025 (WHO RRA v.2, WHO RRA v.3).
Nigeria: As of epidemiological week 34, Nigeria reported 16 997 suspected cases, including 12 491 laboratory-confirmed cases and 596 deaths (CFR: 3.51%), recording the highest number of cases in the WHO African Region. Cases were reported across 24 of 36 states, with the highest numbers in the Kano (7 830), Bauchi (2 696), Katsina (2 144), Borno (1 907) and Sokoto (787) states. Cases reported from these five states accounted for 90% of all cases. The weekly CFR increased from 2.9% early in 2026 to 7.9% in recent weeks (WHO Weekly Bulletin on Outbreak and other Emergencies, WHO RRA v.3). In 2025, a total of 15 273 confirmed cases had been reported from 25 states and in 2024, a total of 10 714 confirmed cases had been reported from 19 states (WHO RRA v.2).
Senegal: Following notification of the first case in epidemiological week 30 of 2026, 13 laboratory-confirmed cases and two deaths, including one probable death (CFR: 15.4%), were reported to WHO between 20 July and 16 August 2026. All cases were younger than 15 years, with a median age of 5 years. The outbreak initially affected the Kedougou and Saraya health districts (WHO Weekly Bulletin on Outbreak and other Emergencies, WHO RRA v.3). In an update provided by the Ministry of Health in Senegal, as of 4 October 2026, a total of 248 confirmed cases, including 11 deaths, were
reported across 51 health districts in 13 regions. The highest number of cases were recorded in the Dakar (42), Kedougou (35) and Diourbel (33) regions (Ministry of Health and Social Action Senegal, Seneweb).
South Africa: Between 29 December 2025 and 20 August 2026, 43 suspected cases of respiratory diphtheria were reported to WHO, including 38 laboratory-confirmed and five probable cases. Eight deaths (CFR: 18.6%) were reported. Laboratory-confirmed cases were reported mostly in Western Cape, Limpopo and Gauteng provinces. Their median age was 23 years (range: 5-72 years), and 68% were adults (WHO RRA v.3). As of 13 September 2026, one additional laboratory-confirmed case was reported in the diphtheria situational report published by the National Institute of Communicable Diseases, South Africa (NICD), resulting in a total of 39 confirmed cases of respiratory diphtheria detected in the country since 29 December 2025.
Algeria: To date, no updated epidemiological data is available for Algeria for 2026. However, according to historical data submitted to WHO up until October 2025, a total of 13 suspected cases, including eight laboratory-confirmed cases and two deaths (CFR: 15.4%), were reported between 8 and 19 October 2025. Previously, as of 25 May 2025, 915 suspected cases had been reported, including 299 laboratory-confirmed cases and 119 deaths (CFR: 13%) (WHO RRA v.2).
Several surveillance gaps and data limitations affect the interpretation of epidemiological trends, including reporting delays, case reclassifications, delayed, incomplete or retrospective reporting, low laboratory confirmation rates, challenges in case management, and missing demographic and vaccination-status data. Additionally, differences in reporting periods and case definitions mean that comparisons across countries should be interpreted cautiously.
ECDC assessment
Most EU/EEA countries have very high vaccination coverage for the primary course of diphtheria-containing vaccines. In the countries with high vaccination coverage, the risk to the general population is assessed as very low, but there could be sporadic cases among unvaccinated individuals or those with incomplete vaccination. Travellers to the regions with active case transmission should ensure they are up to date with vaccinations.