Comoros

The Union of the Comoros is an archipelago of three major islands in the northern Mozambique Channel, roughly 300 kilometres off the north-west coast of Madagascar and immediately north of the French territory of Mayotte. Population approximately 900,000 across Grande Comore, Anjouan, and Moheli. Malaria is endemic; health system capacity is constrained by limited diagnostic infrastructure and periodic drug-supply gaps. The islands' relationship with Mayotte is politically complex: Comoros claims Mayotte as its fourth island but it voted in 2009 to remain French, and clandestine migration creates a mobile cross-border population.

The two territories share a Plasmodium falciparum malaria transmission zone, and irregular population movement between Comoros and Mayotte is a documented driver of imported malaria cases in both directions. In the current alert, Mayotte recorded a 4.2-fold surge to 25 cases per week in weeks 18 to 20 of 2026, concentrated in southern municipalities closest to the Comorian coast. ECDC surveillance does not extend to Comorian territory, meaning the upstream reservoir burden is unmeasured. Any sustained rise in local Comorian transmission will continue to seed Mayotte regardless of island-level vector-control measures.