The World Health Organization (WHO) has launched a preventive vaccination campaign to protect more than 252,500 highly vulnerable people against cholera in Sudan’s North and South Darfur states, the U.N. agency announced on Sunday.

The campaign targets the localities of Tawila in North Darfur and Kass in South Darfur. It comes ahead of the critical rainy season, a period historically marked by heightened disease transmission, escalating food insecurity, and severe logistical disruptions that block the delivery of humanitarian aid.

Pervasive displacement, coupled with severely compromised access to clean water and sanitation services, has left both states facing a high risk of an imminent cholera outbreak.