Publications by authors named "Etienne Gignoux"

Background: Hepatitis E virus (HEV) is a leading cause of acute viral hepatitis, particularly in Asia and Africa, where HEV genotypes 1 and 2 are prevalent. Although a recombinant vaccine, Hecolin, is available, it has not been used to control outbreaks. The licensed three-dose regimen might pose challenges for it to be an impactful outbreak control tool.

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Background: Epidemic forms of hepatitis E cause high mortality among pregnant people, with case fatality risks over 30% and adverse fetal outcomes. In 2022, the first mass reactive vaccination campaign against hepatitis E was conducted in South Sudan with the HEV239 vaccine. We aimed to assess whether vaccination against hepatitis E in pregnancy increases the risk of fetal loss in a cohort of vaccinated and unvaccinated pregnant people.

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Background: The recombinant vesicular stomatitis virus-Zaire Ebola virus (rVSV-ZEBOV) vaccine is the only WHO prequalified vaccine recommended for use to respond to outbreaks of Ebola virus (species Zaire ebolavirus) by WHO's Strategic Advisory Group of Experts on Immunization. Despite the vaccine's widespread use during several outbreaks, no real-world effectiveness estimates are currently available in the literature.

Methods: We conducted a retrospective test-negative analysis to estimate effectiveness of rVSV-ZEBOV vaccination against Ebola virus disease during the 2018-20 epidemic in the Democratic Republic of the Congo, using data on suspected Ebola virus disease cases collected from Ebola treatment centres.

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Article Synopsis
  • The rVSVΔG-ZEBOV-GP vaccine shows significant protective effects against death in patients with confirmed Ebola virus disease, based on a study of 2,279 patients in the Democratic Republic of the Congo.
  • Improvements in survival rates were observed in vaccinated individuals, with case fatality risk dropping from 56% in unvaccinated patients to 25% in vaccinated patients.
  • The effectiveness of the vaccine increased the longer the time from vaccination to the onset of symptoms, with notable decreases in risk based on how many days prior to symptoms the patient was vaccinated.
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Introduction: Hepatitis E (HEV) genotypes 1 and 2 are the common cause of jaundice and acute viral hepatitis that can cause large-scale outbreaks. HEV infection is associated with adverse fetal outcomes and case fatality risks up to 31% among pregnant women. An efficacious three-dose recombinant vaccine (Hecolin) has been licensed in China since 2011 but until 2022, had not been used for outbreak response despite a 2015 WHO recommendation.

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Although seroprevalence studies have demonstrated the wide circulation of SARS-COV-2 in African countries, the impact on population health in these settings is still poorly understood. Using representative samples of the general population, we evaluated retrospective mortality and seroprevalence of anti-SARS-CoV-2 antibodies in Lubumbashi and Abidjan. The studies included retrospective mortality surveys and nested anti-SARS-CoV-2 antibody prevalence surveys.

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  • The study investigated the level of exposure to SARS-CoV-2 in Koutiala district, Mali, using seroprevalence data from blood donors between January and June 2020, aiming to assess community transmission and inform public health responses.
  • Results showed a significant difference in seroprevalence estimates: 24.6% using a rapid test and 70.2% with an ECLIA test, suggesting that the actual exposure to the virus was higher than what was reported through official case surveillance.
  • The findings highlighted the limitations of the national surveillance system in detecting true incidence rates, and indicated a need for further research to validate the testing methods before they can be reliably
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Background: Angumu health zone in Ituri, Democratic Republic of Congo, is a highly malaria-endemic area with an overburdened health system and hosting internally displaced persons (IDP). The World Health Organization recommends mass drug administration (MDA) for malaria in complex emergencies. Therefore, three MDA rounds were implemented by Ministry of Public Health and Médecins sans Frontières from September 2020 to January 2021 in four health areas selected for epidemiological (high malaria incidence) and logistic reasons.

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Introduction: Cholera outbreaks in fragile settings are prone to rapid expansion. Case-area targeted interventions (CATIs) have been proposed as a rapid and efficient response strategy to halt or substantially reduce the size of small outbreaks. CATI aims to deliver synergistic interventions (eg, water, sanitation, and hygiene interventions, vaccination, and antibiotic chemoprophylaxis) to households in a 100-250 m 'ring' around primary outbreak cases.

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  • A survey conducted in Omdurman, Sudan, between March and April 2021 found that 54.6% of the population tested positive for antibodies against SARS-CoV-2, indicating prior infection.
  • The data revealed a significant increase in death rates, with a 74% rise among individuals over 50 years old during the first year of the COVID-19 pandemic.
  • These findings highlight the prevalence of COVID-19 in the community and its severe impact on older populations.
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  • Snakebite envenoming is a significant public health issue, leading to an estimated 81,000-138,000 deaths annually worldwide, with Nepal identified as an endemic area needing more research.
  • A cross-sectional survey conducted in Nepal's Terai lowlands revealed a snakebite incidence rate of 262 per 100,000 people, with 48.8% of victims envenomed and a mortality rate of 7.8%.
  • The study highlights the disparities in impact, with a higher incidence among females and children, and calls for improved prevention and access to treatment for both humans and domestic animals.
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Background: Camps of forcibly displaced populations are considered to be at risk of large COVID-19 outbreaks. Low screening rates and limited surveillance led us to conduct a study in Dagahaley camp, located in the Dadaab refugee complex in Kenya to estimate SARS-COV-2 seroprevalence and, mortality and to identify changes in access to care during the pandemic.

Methods: To estimate seroprevalence, a cross-sectional survey was conducted among a sample of individuals (n = 587) seeking care at the two main health centres and among all household members (n = 619) of community health workers and traditional birth attendants working in the camp.

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Background: In 2017, Field access was considerably limited in the Far North region of Cameroon due to the conflict. Médecins Sans Frontieres (MSF) in collaboration with Ministry of health needed to estimate the health situation of the populations living in two of the most affected departments of the region: Logone-et-Chari and Mayo-Sava.

Methods: Access to health care and mortality rates were estimated through cell phone interviews, in 30 villages (clusters) in each department.

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Background: Measles continues to circulate in the Democratic Republic of Congo, and the country suffered from several important outbreaks over the last 5 years. Despite a large outbreak starting in the former province of Katanga in 2010 and the resulting immunization activities, another outbreak occurred in 2015 in this same region. We conducted measles seroprevalence surveys in four health zones (HZ) in the former Katanga Province in order to assess the immunity against measles in children 6 months to 14 years after the 2015 outbreak.

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Introduction: Lahe Township belongs to Myanmar`s Naga Self-administered Zone, which is one of the most remote and mountainous areas in Myanmar. However, the limited health data available for the region suggests that there could be neglected health needs that require attention. The purpose of this study was to assess the health status of the population of Lahe Township.

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Objective: To rapidly increase childhood immunization through a preventive, multi-antigen, vaccination campaign in Mambéré-Kadéï prefecture, Central African Republic, where a conflict from 2012 to 2015 reduced vaccination coverage.

Methods: The three-round campaign took place between December 2015 and June 2016 using: (i) oral poliomyelitis vaccine (OPV); (ii) combined diphtheria, tetanus and pertussis (DTP) vaccine, type B (Hib) and hepatitis B (DTP-Hib-hepatitis B) vaccine; (iii) pneumococcal conjugate vaccine (PCV); (iv) measles vaccine; and (v) yellow fever vaccine. Administrative data were collected on vaccines administered by age group and vaccination coverage surveys were carried out before and after the campaign.

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  • A large measles epidemic occurred in 2013 in the Aketi Health Zone of the Democratic Republic of Congo, affecting 7880 people across 1424 households, with an attack rate of 14.0% overall and 35.0% among children under 5.
  • The case fatality rate was estimated at 4.2%, with a higher rate of 6.1% in young children, revealing the risks related to distance from healthcare and lack of care.
  • Low pre-outbreak vaccination coverage (76%) and delayed vaccination efforts significantly contributed to the high attack rate, but a robust case management approach helped reduce fatalities during the crisis.
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  • Large outbreaks of hepatitis E virus (HEV) have been noted among displaced populations in Africa, particularly in Juba, South Sudan, where a serological survey was conducted.
  • The study involved testing serum samples from 206 residents of an internally displaced person camp for HEV antibodies, revealing a high age-adjusted seroprevalence of 71% for historical exposure and only 4% for recent infection.
  • Results suggest that HEV exposure rates in the camp are more than two times higher compared to individuals' home states, highlighting the need for improved disease surveillance to better understand and manage HEV transmission in similar contexts.
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The Ebola epidemic in West Africa was stopped by an enormous concerted effort of local communities and national and international organizations. It is not clear, however, how much the public health response and behavioural changes in affected communities, respectively, contributed to ending the outbreak. Here, we analyse the epidemic in Lofa County, Liberia, lasting from March to November 2014, by reporting a comprehensive time line of events and estimating the time-varying transmission intensity using a mathematical model of Ebola transmission.

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