Targeted vaccination against Hepatitis E in South Sudan: Assessment of a campaign in the Fangak region
You led a field study during a Hepatitis E epidemic in Old Fangak, South Sudan. Could you tell us about the main challenges encountered during this study?
Joe Aumuller: The Hepatitis E epidemic that hit Fangak County posed a monumental challenge, both for the vaccination campaign and for the study we conducted in parallel with Epicentre. The first major obstacle was population mobility. The region is plagued by flooding and civil unrest, which has led many people to move between different villages across South Sudan. Many of the women we targeted for vaccination received their first dose in one village and their second dose elsewhere, which made it difficult to accurately estimate vaccination coverage.
Our study evaluated not only the coverage amongst women aged 16 to 45 targeted by the campaign, but also the perceptions and experiences of men, those of different ages, those involved in the campaign, and members across the local social hierarchy. Despite acceptance of the vaccine, we found resistance to the strategy targeting exclusively women aged 16-45 years old. Patriarchal social structures complicated interactions with women: in some families it was the men or heads of household who answered for them, even if the eligible woman was present.
What other logistical and cultural obstacles did you encounter during the study?
Joe Aumuller: Conditions on the ground were extremely difficult. Access to some villages was problematic due to flooded swamp and tall grass areas with no roads nor transport infrastructure. In more remote areas teams were forced to overnight in the bush for multi-day boat trips in order to reach study participants.
We also had difficulties in recruiting women to our survey teams which may have played a role in the access and information shared in interviews regarding women’s perceptions, vaccination status, vaccine side effects and pregnancy status. In many communities, women are reluctant to talk openly about their health status, especially in front of men.
Another challenge was that recruitment and study activities were scheduled during the day. At these times, many women were busy with daily chores such as harvesting water lilies or selling local produce. This likely contributed to low participation, particularly among unvaccinated women, who were already difficult to recruit.
Despite these challenges, what are the main findings of this study?
Joe Aumuller: The results of the study are surprising but encouraging. We observed high vaccination coverage: 94% of eligible women received at least one dose of Hepatitis E vaccine, while 77% completed the two-dose series, according to recall or vaccination cards. However, coverage confirmed by vaccination card was lower, with 67% for one dose and 53% for two doses. We also documented a relatively high rate of new symptoms within 72 hours of vaccination, of which fever, headache and fatigue were the most common.
Despite some criticism of the female-only vaccination strategy, the campaign succeeded in reaching many women, demonstrating a real fear of the virus and general acceptance of the vaccine. Further, fewer severe cases have been observed at the Old Fangak Hospital by MSF since vaccination. This success reflects the effectiveness of awareness-raising, even in a context as complex as that of the MSF Old Fangak project.
What lessons have you learned from your experience in the field?
Joe Aumuller: This study reminds us of the importance of adapting vaccination and research strategies to local realities, both logistical and cultural. Working in such remote contexts, with limited infrastructure and mobile populations, requires flexibility that we sometimes struggle to achieve. It is also essential to prepare and account for key contextual components like gender dynamics, logistics, and limited geodata from the outset of study planning to avoid bias and challenges in data collection. This will enable us to improve the scope and effectiveness of future interventions, while strengthening our understanding of the social barriers to vaccination.
©Brienne Prusak
