Diphtheria outbreak in Somalia: a weekly sitrep on the recent health crisis-2025

TL;DR

A diphtheria outbreak in Somalia is worsening due to low vaccination coverage and weak health systems, with children under five most affected.

Contribution

The study provides a detailed weekly analysis of the diphtheria outbreak in Somalia, linking it to immunization gaps and health system challenges.

Findings

By Epi-week 33, 1811 suspected diphtheria cases and 89 deaths were recorded, with children under five accounting for 56% of cases.

DTP-1 coverage increased to 79% in 2022 but plateaued at 70% in 2024, remaining insufficient for herd immunity.

Outbreak control is hindered by limited vaccine and antitoxin supplies, insecurity, and access barriers.

Abstract

The global diphtheria incidence has fallen following widespread use of the diphtheria–tetanus–pertussis (DTP) vaccine; pockets of low coverage and disrupted health services continue to fuel outbreaks. Somalia, already challenged by conflict-related displacement and fragile health infrastructure, declared a national diphtheria outbreak on 19 August 2025. We analysed weekly case-based surveillance data reported through Somalia’s Integrated Disease Surveillance and Response (IDSR) system and the DHIS2 electronic platform (Epi-weeks 1–33, 2025) on the platform. Vaccination-coverage trends were extracted from WHO/UNICEF Estimates of National Immunization Coverage (WUENIC, 2000–2024). Supplementary information was obtained from the Ministry of Health situation reports and partner briefs. By Epi-week 33 (ending 17 August 2025), 1811 suspected diphtheria cases (17 laboratory-confirmed) and 89 deaths were recorded (case-fatality rate 5%). Children < 5 years accounted for 56% of cases; 87% of patients had no documented diphtheria immunization. Weekly incidence accelerated sharply after Epi-week 20, with the largest surges in Puntland, South-West State and the Benadir Regional Administration. DTP-1 coverage increased from 40 to 60% (2000–2018) to 79% in 2022 but plateaued at 70% in 2024; DTP-3 coverage reached 71% in 2022 yet remains insufficient for herd protection. Despite targeted ring vaccination and distribution of diphtheria antitoxin (DAT), constrained vaccine and DAT supplies, insecurity, and access barriers hamper outbreak control. Somalia’s diphtheria resurgence underscores how conflict, displacement, and uneven immunization can reverse hard-won gains against vaccine-preventable diseases. Closing routine-coverage gaps, guaranteeing timely DAT and antibiotic access, expanding real-time surveillance, and intensifying community engagement are urgent priorities to halt transmission and avert additional deaths. Prompt mobilization of national leadership, donors, and technical partners is essential to contain the outbreak and restore progress toward diphtheria elimination.

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