The medical charity said violence and displacement since 2025 have repeatedly interrupted immunization programs, especially in overcrowded displacement camps and remote communities where access to healthcare remains limited.

MSF said it is calling on donors, humanitarian partners, and parties to the conflict to guarantee safe access for health workers and allow uninterrupted delivery of life-saving aid.

According to the organization, vaccination campaigns were expanded in several parts of the country during the first months of 2026 to respond to growing health risks.

In Ayod and Duk counties, more than 89,000 people were vaccinated against cholera, while thousands of children also received measles and polio vaccines. In the Aweil region, over 41,000 vaccine doses against diseases including malaria, measles, and pneumonia were administered.

MSF also said it supported measles outbreak responses in Abyei and Tonj South, where more than 40,000 children were vaccinated through mobile and fixed health teams operating in displacement sites, border areas, and remote communities.

The organization said routine immunization services also continued in Renk, Yei, Kajo Keji, and Greater Pibor, reaching refugee, returnee, and vulnerable communities.

However, MSF warned that insecurity and limited access continue to disrupt vaccination campaigns in several counties, leaving many children without protection against deadly diseases.

Hussein Philemon Mahimbo, who is in charge of an MSF measles vaccination campaign in Tonj South County, said interrupted vaccination efforts increase the risk of outbreaks.

“Every child we reach with a vaccine is a child protected from diseases that are now largely controllable,” he said. “But in South Sudan, access is still dictated by conflict and displacement. When vaccination is interrupted, outbreaks are not a risk — they are a certainty.”

MSF said strengthening routine immunization, ensuring reliable vaccine supplies, and improving access to hard-to-reach communities are critical to preventing future outbreaks and saving lives.