Better monitoring of childhood vaccinations and stronger community follow-up of children who miss doses could help reduce immunization dropouts in South Sudan, a new study has found.
The study, published in PLOS One, examined 14 health facilities in Maridi County, Western Equatoria State, over three months in 2023.
The researchers found that facilities that consistently updated their immunization monitoring charts recorded significantly lower dropout rates.
“Facilities with updated monitoring charts were significantly less likely to record high dropout rates,” the researchers said.
The study also found that three of the 14 facilities, or 21 percent, had no immunization monitoring chart, while 28.6 percent recorded dropout rates above 10 percent. Half of the facilities achieved dropout rates below 10 percent.
Community health workers also appeared to play an important role in keeping children on schedule. Boma Health Workers (BHWs), who operate at the community level under South Sudan’s Boma Health Initiative, help mobilize families, identify children who miss vaccinations and refer them back to health facilities.
Facilities with Boma Health Workers accounted for 91.7 percent of facility-month observations in the low-dropout category, compared with 37.5 percent among high-dropout observations.
Most importantly, the researchers said the findings point to the importance of linking health facilities with communities rather than relying on a single monitoring mechanism.
“Facility-based monitoring tools used by health workers … and community-based monitoring carried out by BHWs were each independently associated with lower dropout rates, and their combination appears to have a complementary effect,” the authors wrote.
South Sudan’s Ministry of Health describes the Boma Health Initiative as the country’s national community health strategy, designed to extend preventive and basic health services to households, particularly in remote areas.
Its community health workers are also tasked with supporting immunization through health education, community mobilization and vaccination services.
The findings come as South Sudan continues its efforts to strengthen routine immunization. The World Health Organization (WHO) reported that the country’s Penta-3 coverage increased from 82 percent in 2023 to 87 percent by mid-December 2024 following intensified immunization efforts.
The response included vaccination campaigns after measles outbreaks were confirmed in 23 counties in 2024.
Globally, WHO says monitoring vaccination data at the subnational level is critical for identifying immunization gaps and tailoring strategies to reach children who are being missed.
Meanwhile, in 2025, 13.5 million children worldwide received no initial DTP dose, while another six million were partially vaccinated, according to WHO reports.
The Maridi researchers caution, however, that their study does not prove that monitoring systems directly caused lower dropout rates because the facilities were not randomly assigned.
They therefore recommend the consistent use of monitoring and defaulter-tracing tools, the expansion of Boma Health Workers to facilities without them, and better use of immunization data to prevent vaccine stockouts.
IMAGE CREDIT