Acute hepatitis E – South Sudan

5 May 2023

Situation at a glance

On 14 April 2023, the Ministry of Health (MoH) of South Sudan declared an outbreak of the hepatitis E Virus (HEV) in Wau city, the capital of Western Bahr el-Ghazal state and one of the largest cities in South Sudan. Between 23 March 2023 and 13 April 2023, a total of 91 HEV suspected cases have been reported from Wau, of which 35 are confirmed; there have been five deaths reported (case fatality ratio [CFR] 5.5%). A multidisciplinary national rapid response team has been deployed by the MoH, supported by WHO, to conduct an epidemiological investigation, determine the extent of the outbreak, identify exposures or risk factors to prevent further spread and implement appropriate preventive measures. 

HEV is transmitted by the fecal-oral route, mainly through contaminated water. Hepatitis E is found worldwide and is common in developing countries with inadequate water supply, limited access to adequate clean drinking water, poor environmental sanitation, personal hygiene, and limited health services, or areas of humanitarian emergencies. 

Cases of the hepatitis E virus have been reported in the Bentiu camp for internally displaced persons (IDPs) in South Sudan since 2018, with seasonal upsurges reported yearly, particularly during the rainy season due to floods leading to contamination of drinking water. There is a risk of international spread of the disease as South Sudan shares borders with Sudan and Ethiopia, with substantial traffic between them. The situation is further aggravated by the highly mobile IDP and refugee population, mainly from Rubkona county, Unity State, where the Bentiu IDP camp is located. 

Description of the outbreak

On 14 April 2023, the Ministry of Health of South Sudan declared an outbreak of the hepatitis E Virus in Wau city, the capital of Western Bahr el-Ghazal State.

On 22 March 2023, the MoH was notified of a cluster of cases with jaundice and several deaths. In response, the MoH, supported by WHO, immediately deployed a multidisciplinary national rapid response team to conduct an epidemiological investigation, characterize the event, determine its magnitude, and identify exposures or risk factors to guide control and prevention measures.

Between 23 March 2023 and 13 April 2023, a total of 91 suspected cases of hepatitis E virus were reported and five were fatal (CFR 5.5%). A total of 44 blood samples were collected and tested for HEV IgM antibodies, of which 79% (n = 35) were confirmed. Most cases (93%) have been reported from Nazareth village in Wau South. The median age of cases is 20 years (range 2 – 71 years). Males are most affected, accounting for 74% of all reported cases.  

To validate the positive results, 24 samples were shipped to the Uganda Virus Research Institute and Medical Research Council virology laboratory in Uganda on 17 April 2023. On 24 April 2023, ten of the 24 samples tested positive for HEV by real time polymerase chain reaction (RT-PCR). Further detailed investigation and sequencing of samples are ongoing.

Hepatitis E Virus (HEV) cases have been consistently reported in South Sudan since 2018, with recurrent outbreaks in Bentiu, Rubkona county, in the Unity state (central-north part of South Sudan), where the Bentiu IDP camp with around 170 000 individuals is located.

Between 2018 and 29 November 2021, a total of 1707 suspected cases, including 104 confirmed and 12 deaths (five deaths in 2021 alone) were reported in the country. All confirmed cases were tested by PCR at the Uganda Virus Research Institute.

In 2022, 2110 cases were reported in Bentiu IDP camp, Unity state. Following the continued detection of cases in March, April, and October 2022, Médecins Sans Frontières (MSF) and the MoH jointly carried out the first hepatitis E vaccination campaign in Bentiu IDP camp. Around 25 000 people, including pregnant women, received the vaccine out of around 170 000 people in the camp. 

As of 19 March 2023, 4009 cases of hepatitis E, including 27 deaths (CFR: 1%) have been reported from Bentiu IDP camp. 

Epidemiology of disease

Hepatitis E is a liver disease caused by the hepatitis E virus (HEV). Hepatitis E is found worldwide and is common in developing countries with limited access to adequate clean drinking water, poor sanitation and personal hygiene, limited health services or in areas of humanitarian emergencies. 

The hepatitis E virus is transmitted by the fecal-oral route, mainly through contaminated water. The risk factors for hepatitis E are related to poor sanitation conditions, allowing the viruses excreted in the feces of infected subjects to reach water intended for human consumption. The infection resolves spontaneously in 2-6 weeks with a 0.5-4% lethality. Fulminant hepatitis, severe liver function impairment caused by HEV, is more common in pregnancy. Pregnant women, especially in their second and third trimesters, are at increased risk of acute liver failure, fetal loss, and mortality: the case-fatality rate can be as high as 20-25% in women in the last trimester of pregnancy. 

Globally, most human infections with HEV are attributed to genotypes 1 and 2, which primarily affect humans in developing countries where contamination of drinking water and lack of adequate sanitation are common, especially in Sub-Saharan Africa and Asia. 

Public health response

The South Sudan MoH continues to work with WHO and partners to ensure response efforts are fully implemented and the people of South Sudan are protected from the risk of HEV. The MoH has initiated the following key response actions:

Leadership and coordination

  • The Water, Sanitation and Hygiene (WASH) Cluster at the state and national levels is tracking the progress of the response. 
  • WASH partners in hotspot counties (Wau and Jur River) continue to focus on integrating with the Infection Prevention and Control (IPC) and Risk Communication and Community Engagement (RCCE) pillars of the state MoH (SMoH) Taskforce.
  • The WASH Cluster at the state level has established twice-weekly meetings.
  • WASH Cluster sub-national coordinators attend SMoH Taskforce meetings to get updates and relay them to partners. 
  • Immediate activation of the Public Health Emergency Operations Center and all response pillars: coordination, surveillance, case management, WASH, IPC, RCCE, safe and dignified burial, points of entry, and logistics. 

WASH

  • Wherever required, WASH actors continue to provide technical guidance to health partners in implementing IPC in target health facilities and HEV treatment/isolation centres where the health partner does not have WASH capacity. 
  • The WASH Cluster at the state level is coordinating with health partners to identify affected households for the provision of WASH-related non-food items and hygiene promotion.

Surveillance and case management

  • Maintaining the multi-disciplinary national rapid response team in Wau to continue supporting the SMoH and partners to mount a full-scale response in the areas of active case search and line listing of cases, additional sample collection and testing at the Wau Teaching Hospital and the National Public Health Laboratory, case management and IPC measures to health facilities, improving WASH conditions, and IPC in affected communities. 

WHO risk assessment

Cases of hepatitis E virus have been detected in South Sudan and the Bentiu IDP camp since 2018. If the WASH conditions are not improved, the potential risk to human health is high, especially for pregnant women and infants, as mother-to-infant transmission of HEV (during the third trimester of gestation) has been reported.  

The risk at the national level is assessed as high due to:

  • Poor sanitation and hygiene practices, especially in the IDP camp;
  • Limited availability of safe drinking water;
  • Poor access to essential medical services;
  • The presence of a large IDP population in South Sudan;
  • Financial constraints impacting capacities to effectively contain the outbreak and limited local capacity to carry out response activities effectively;
  • The limited availability of vaccine supply;
  • Population movements;
  • High risk of death in pregnant women in the absence of HEV vaccine introduction;  

The overall risk at the regional level is considered moderate due to the risk of disease spread between the mobile IDP populations and refugees who cross the borders between South Sudan, Sudan, and Ethiopia. In 2018, genomic sequencing of isolates from HEV cases reported in Bentiu IDP camp showed HEV genotype 1, closely related to strains isolated in the Chad basin and Northern Uganda. This highlights the risk of extensive regional spread in the current context that involves IDPs, refugees, and other populations of humanitarian concern.  

At the global level, the risk is low. 

WHO advice

Prevention is the most effective approach against this disease. At the community level, the most important interventions to reduce HEV transmission are safe drinking water, quality standards for public water supplies, and adequate sanitation. At the individual level, infectious risks can be reduced by maintaining hygiene practices such as washing hands with clean water and soap, especially before handling food, avoiding consumption of water and/or ice of unknown purity, and following WHO hygiene practices for food safety. 

To prevent the spread of acute hepatitis E, WHO recommends improving access to safe drinking water and adequate sanitation. The drinking water quality should be regularly monitored in neighborhoods affected by this epidemic. Coverage of latrines and drinking water sources should be increased to prevent open defecation and to ensure hand hygiene.

Health promotion and prevention activities, as well as ensuring early, appropriate, and equitable healthcare services to combat hepatitis E epidemics, can help improve public health outcomes, especially in resource-limited settings. Since the incubation period for hepatitis E ranges from two to 10 weeks, cases may continue to occur up to 10 weeks after measures to ensure safe water, sanitation, and hygiene promotion have been adopted. 

Interventions must continue to target vulnerable populations by establishing or strengthening antenatal diagnosis for pregnant women with symptoms, improving the population's hygiene conditions, strengthening national capacities for diagnosis and clinical case management, and cross-border collaboration with neighbouring countries. 

There is no specific treatment for the clinical management of patients. There may be specific situations, such as outbreaks, where the risk of hepatitis E or its complications or mortality is particularly high. The recombinant hepatitis E vaccine, Hecolin, has been developed for commercialization and licensed in China and Pakistan. While WHO does not recommend the introduction of the vaccine as part of national routine population immunization programs, WHO recommends that national authorities consider using the vaccine in outbreak settings, including in populations at high risk, such as pregnant women.

Further information

Citable reference: World Health Organization (5 May 2023). Disease Outbreak News; Acute Hepatitis E – South Sudan. Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON466