Deaths, late deaths, and role of infecting dose in Ebola virus disease in Sierra Leone: retrospective cohort study

Individual and household risk factors for Ebola disease among household contacts in Mubende and Kassanda districts, Uganda, 2022

BACKGROUND

In 2022, an Ebola disease outbreak caused by Sudan virus (SUDV) occurred in Uganda, primarily affecting Mubende and Kassanda districts. We determined risk factors for SUDV infection among household members (HHM) of cases.

METHODS

We conducted a case-control and retrospective cohort study in January 2023. Cases were RT-PCR-confirmed SUDV infection in residents of Mubende or Kassanda districts during the outbreak. Case-households housed a symptomatic, primary case-patient for ≥ 24 h and had ≥ 1 secondary case-patient with onset < 2 weeks after their last exposure to the primary case-patient. Control households housed a case-patient and other HHM but no secondary cases. A risk factor questionnaire was administered to the primary case-patient or another adult who lived at home while the primary case-patient was ill. We conducted a retrospective cohort study among case-household members and categorized their interactions with primary case-patients during their illnesses as none, minimal, indirect, and direct contact. We conducted logistic regression to explore associations between exposures and case-household status, and Poisson regression to identify risk factors for SUDV infection among HHM.

RESULTS

Case- and control-households had similar median sizes. Among 19 case-households and 51 control households, primary case-patient death (adjusted odds ratio [ORadj] = 7.6, 95% CI 1.4-41) and ≥ 2 household bedrooms (ORadj=0.19, 95% CI 0.056-0.71) were associated with case-household status. In the cohort of 76 case-HHM, 44 (58%) were tested for SUDV < 2 weeks from their last contact with the primary case-patient; 29 (38%) were positive. Being aged ≥ 18 years (adjusted risk ratio [aRRadj] = 1.9, 95%CI: 1.01-3.7) and having direct or indirect contact with the primary case-patient (aRRadj=3.2, 95%CI: 1.1-9.7) compared to minimal or no contact increased risk of Sudan virus disease (SVD). Access to a handwashing facility decreased risk (aRRadj=0.52, 95%CI: 0.31-0.88).

CONCLUSION

Direct contact, particularly providing nursing care for and sharing sleeping space with SVD patients, increased infection risk among HHM. Risk assessments during contact tracing may provide evidence to justify closer monitoring of some HHM. Health messaging should highlight the risk of sharing sleeping spaces and providing nursing care for persons with Ebola disease symptoms and emphasize hand hygiene to aid early case identification and reduce transmission.

Updated picture of SARS-CoV-2 variants and mutations

The worldwide burden of coronavirus disease 2019 (COVID-19) is still unremittingly prosecuting, with nearly 300 million infections and over 5.3 million deaths recorded so far since the origin of the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) pandemic at the end of the year 2019. The fight against this new highly virulent beta coronavirus appears one of the most strenuous and long challenges that humanity has ever faced, since a definitive treatment has not been identified so far. The adoption of potentially useful physical preventive measures such as lockdowns, social distancing and face masking seems only partially effective for mitigating viral spread, though efficacy and continuation of such measures on the long term is questionable, due to many social and economic reasons. Many COVID-19 vaccines have been developed and are now widely used, though their effectiveness is challenged by several aspects such as low uptake and limited efficacy in some specific populations, as well as by continuous emergence of new mutations in the SARS-CoV-2 genome, accompanying the origin and spread of new variants, which in turn may contribute to further decrease the effectiveness of current vaccines and treatments. This article is hence aimed to provide an updated picture of SARS-CoV-2 variants and mutations that have emerged from November 2019 to present time (i.e., early December 2021).

Systematic analysis of infectious disease outcomes by age shows lowest severity in school-age children

The COVID-19 pandemic has ignited interest in age-specific manifestations of infection but surprisingly little is known about relative severity of infectious disease between the extremes of age. In a systematic analysis we identified 142 datasets with information on severity of disease by age for 32 different infectious diseases, 19 viral and 13 bacterial. For almost all infections, school-age children have the least severe disease, and severity starts to rise long before old age. Indeed, for many infections even young adults have more severe disease than children, and dengue was the only infection that was most severe in school-age children. Together with data on vaccine response in children and young adults, the findings suggest peak immune function is reached around 5-14 years of age. Relative immune senescence may begin much earlier than assumed, before accelerating in older age groups. This has major implications for understanding resilience to infection, optimal vaccine scheduling, and appropriate health protection policies across the life course.

Ebola virus disease in children in Conakry and Coyah Ebola treatment centers and risk factors associated with death

OBJECTIVE

To study Ebola virus disease (EVD) in children aged 15 years and below, and to identify risk factors associated with death.

PATIENTS AND METHODS

Retrospective, multicenter, descriptive, and analytical study of files of children aged 15 years and below in Ebola treatment centers (ETC) of Donka from March 2014 to May 2015. We included all files of children aged 15 years and below hospitalized for EVD in the two ETCs.

RESULTS

A total of 739 patients hospitalized in both ETCs, 146 children aged 15 years and below (20%) were registered during the study period. The mean age of children was 6.73±4.26 years. Most children were aged above five years (65.8%) and the mean time to consultation was 4.34±3.21 days. The main clinical signs were asthenia (78.8%), fever (75.3%), anorexia (53.4%), headache (45.9%), vomiting (41.8%), abdominal pain (29.5%), and diarrhea (28.8%). The case fatality was 48%, including 54.3% in Coyah and 45% in Conakry. Older age (aOR=0.83, 95% CI [0.76-0.95]), fever (aOR=3.28, 95% CI [1.22-8.87]), diarrhea (aOR=2.98, 95% CI [1.19-4.48]), and hemorrhage (aOR=3.13, 95% CI [1.00-10.38]) were independently associated with death due to EVD.

CONCLUSION

EVD remains serious especially in children, with high case fatality. Risk factors independently associated with death were young age, diarrhea, hemorrhage, and fever. Particular attention to these risk factors and vaccination will contribute to improving the prognosis of EVD in children.

Ebola Virus Disease in the Obstetric Population

The clinical management of Ebola created a significant challenge during the outbreak in West Africa, due to the paucity of previous research conducted into the optimum treatment regimen. That left many centres, to some extent, having to ‘work out’ best practice as they went along, and attempting to conduct real time prospective research. Médecins Sans Frontières (MSF) [1] were the only organization to have provided relatively in depth practical guidance prior to the outbreak and this manual was the basis of further planning between the WHO, national Ministry of Health and Sanitation in Sierra Leone, and other relevant stakeholders. Additionally, guidance changed over the epidemic as experience grew. This chapter will describe four key areas in the management of Ebola in West Africa. Firstly, it outlines the most recent WHO guidance; secondly, it looks back at how Ebola was managed in differing low and high resource settings; thirdly it outlines possible and optimal options for managing complications, paying particular attention to some of the controversies faced; fourthly it describes recent and ongoing studies into potential novel therapies that may shape future practice.

Early transmission and case fatality of Ebola virus at the index site of the 2013-16 west African Ebola outbreak: a cross-sectional seroprevalence survey

BACKGROUND

To date, epidemiological studies at the index site of the 2013-16 west African Ebola outbreak in Meliandou, Guinea, have been restricted in their scope. We aimed to determine the occurrence of previously undocumented Ebola virus disease (EVD) cases and infections, and to reconstruct transmission events.

METHODS

This cross-sectional seroprevalence survey of the adult population of Meliandou used a highly specific oral fluid test and detailed interviews of all households in the village and key informants. Each household was interviewed, with all members prompted to describe the events of the outbreak, any illness within the household, and possible contact with suspected cases. Information for deceased individuals was provided by relatives living in the same household. Symptoms were based on Ebola virus Makona variant EVD case definitions (focusing on fever, vomiting, and diarrhoea). For antibody testing, we used an Ebola virus glycoprotein IgG capture enzyme immunoassay developed from a previously validated assay. A maximum exposure level was assigned to every participant using a predetermined scale. We used a generalised linear model (logit function) to estimate odds ratios for the association of sociodemographic variables and exposure level with Ebola virus infection. We adjusted estimates for age and maximum exposure, as appropriate.

FINDINGS

Between June 22, and July 9, 2017, we enrolled 237 participants from 27 households in Meliandou. Two households refused to participate and one was absent. All adults in participating households who were present for the interview provided an oral fluid swab for testing, of which 224 were suitable for analysis. In addition to the 11 EVD deaths described previously, on the basis of clinical description and oral fluid testing, we found two probable EVD deaths and eight previously unrecognised anti-Ebola virus IgG-positive survivors, including one who had mild symptoms and one who was asymptomatic, resulting in a case fatality of 55·6% (95% CI 30·8-78·5) for adults. Health-care work (adjusted odds ratio 6·64, 1·54-28·56; p=0·001) and level of exposure (odds ratio adjusted for linear trend across five levels 2·79, 1·59-4·883; p<0·0001) were independent risk factors for infection.

INTERPRETATION

Ebola virus infection was more widespread in this spillover population than previously recognised (21 vs 11 cases). We show the first serological evidence of survivors in this population (eight anti-Ebola virus IgG seropositive) and report a case fatality lower than previously reported (55·6% vs 100% in adults). These data show the high community coverage achievable by using a non-invasive test and, by accurately documenting the beginnings of the west African Ebola virus outbreak, reveal important insight into transmission dynamics and risk factors that underpin Ebola virus spillover events.

FUNDING

US Food and Drug Administration, Wellcome Trust, and German Research Council.

Surviving Ebola: A historical cohort study of Ebola mortality and survival in Sierra Leone 2014-2015

Background

While a number of predictors for Ebola mortality have been identified, less is known about post-viral symptoms. The identification of acute-illness predictors for post-viral symptoms could allow the selection of patients for more active follow up in the future, and those in whom early interventions may be beneficial in the long term. Studying predictors of both mortality and post-viral symptoms within a single cohort of patients could also further our understanding of the pathophysiology of survivor sequelae.

Methods/Principal findings

We performed a historical cohort study using data collected as part of routine clinical care from an Ebola Treatment Centre (ETC) in Kerry Town, Sierra Leone, in order to identify predictors of mortality and of post-viral symptoms. Variables included as potential predictors were sex, age, date of admission, first recorded viral load at the ETC and symptoms (recorded upon presentation at the ETC). Multivariable logistic regression was used to identify predictors. Of 263 Ebola-confirmed patients admitted between November 2014 and March 2015, 151 (57%) survived to ETC discharge. Viral load was the strongest predictor of mortality (adjusted OR comparing high with low viral load: 84.97, 95% CI 30.87–345.94). We did not find evidence that a high viral load predicted post-viral symptoms (ocular: 1.17, 95% CI 0.35–3.97; musculoskeletal: 1.07, 95% CI 0.28–4.08). Ocular post-viral symptoms were more common in females (2.31, 95% CI 0.98–5.43) and in those who had experienced hiccups during the acute phase (4.73, 95% CI 0.90–24.73).

Conclusions/Significance

These findings may add epidemiological support to the hypothesis that post-viral symptoms have an immune-mediated aspect and may not only be a consequence of high viral load and disease severity.

Ébola, abordaje clínico integral

Introducción. El virus del Ébola, antes llamado fiebre hemorrágica del Ébola, es una enfermedad altamente contagiosa con mortalidad entre 50% y 90%, para la cual existen prometedoras opciones de tratamiento que se encuentran en fase de evaluación y uso compasional.Objetivos. Revisar la mejor evidencia médica publicada y analizar el comportamiento de las epidemias por virus del Ébola, sus manifestaciones clínicas, sus complicaciones, los elementos más significativos para su diagnóstico y las nuevas opciones terapéuticas disponibles, para así aprender y aplicar estas experiencias en nuevos brotes.Materiales y métodos. Se realizó una búsqueda sistemática en las bases de datos PubMed, ProQuest, Embase, Redalyc, Ovid, Medline, DynaMed y ClinicalKey durante el periodo 2009-2017 en el contexto internacional, regional y local.Resultados. La revisión sistemática de artículos aportó un total de 51 430 registros, de los cuales 772 eran elegibles; de estos, 722 no eran relevantes, por lo que quedaron incluidos 50. A punto de partida se pudieron precisar los aspectos objeto de esta revisión.Conclusión. La enfermedad causada por el virus del Ébola, a pesar de su alta mortalidad, puede ser prevenida, diagnosticada oportunamente y tratada con efectividad, lo cual permite evaluar su impacto epidemiológico en las áreas endémicas y a nivel mundial. Existe un potencial arsenal terapéutico en fase de experimentación con resultados prometedores.

Use of verbal autopsy and social autopsy in humanitarian crises

INTRODUCTION

Two billion people live in countries affected by conflict, violence and fragility. These are exceptional situations in which mortality shifts dramatically and in which civil registration and vital statistics systems are often weakened or cease to function. Verbal autopsy and social autopsy (VA and SA) are methods used to assign causes of death and understand the contexts in which these occur, in settings where information is otherwise unavailable. This review sought to explore the use of VA and SA in humanitarian crises, with a focus on how these approaches are used to inform policy and programme responses.

METHODS

A rapid scoping review was conducted on the use of VA and SA in humanitarian crises in low and middle-income countries since 1991. Drawing on a maximum variation approach, two settings of application ('application contexts') were selected and investigated via nine semi-structured expert interviews.

RESULTS

VA can determine causes of death in crisis-affected populations where no other registration system is in place. Combined with SA and active community involvement, these methods can deliver a holistic view of obstacles to seeking and receiving essential healthcare, yielding context-specific information to inform appropriate responses. The contexts in which VA and SA are used require adaptations to standard tools, and new mobile developments in VA raise specific ethical considerations. Furthermore, collecting and sythesising data in a timely, continuous manner, and ensuring coordination and communication between agencies, is important to realise the potential of these approaches.

CONCLUSION

VA and SA are valuable research methods to foster evidence-informed responses for populations affected by humanitarian crises. When coordinated and communicated effectively, data generated through these methods can help to identify levels, causes and circumstances of deaths among vulnerable groups, and can enable planning and allocating resources effectively, potentially improving health system resilience to future crises.

Frequency of reporting on patient and public involvement (PPI) in research studies published in a general medical journal: a descriptive study

OBJECTIVES

While documented plans for patient and public involvement (PPI) in research are required in many grant applications, little is known about how frequently PPI occurs in practice. Low levels of reported PPI may mask actual activity due to limited PPI reporting requirements. This research analysed the frequency and types of reported PPI in the presence and absence of a journal requirement to include this information.

DESIGN AND SETTING

A before and after comparison of PPI reported in research papers published in The BMJ before and 1 year after the introduction of a journal policy requiring authors to report if and how they involved patients and the public within their papers.

RESULTS

Between 1 June 2013 and 31 May 2014, The BMJ published 189 research papers and 1 (0.5%) reported PPI activity. From 1 June 2015 to 31 May 2016, following the introduction of the policy, The BMJ published 152 research papers of which 16 (11%) reported PPI activity. Patients contributed to grant applications in addition to designing studies through to coauthorship and participation in study dissemination. Patient contributors were often not fully acknowledged; 6 of 17 (35%) papers acknowledged their contributions and 2 (12%) included them as coauthors.

CONCLUSIONS

Infrequent reporting of PPI activity does not appear to be purely due to a failure of documentation. Reporting of PPI activity increased after the introduction of The BMJ's policy, but activity both before and after was low and reporting was inconsistent in quality. Journals, funders and research institutions should collaborate to move us from the current situation where PPI is an optional extra to one where PPI is fully embedded in practice throughout the research process.

Heterogeneities in the case fatality ratio in the West African Ebola outbreak 2013-2016

The 2013–2016 Ebola outbreak in West Africa is the largest on record with 28 616 confirmed, probable and suspected cases and 11 310 deaths officially recorded by 10 June 2016, the true burden probably considerably higher. The case fatality ratio (CFR: proportion of cases that are fatal) is a key indicator of disease severity useful for gauging the appropriate public health response and for evaluating treatment benefits, if estimated accurately. We analysed individual-level clinical outcome data from Guinea, Liberia and Sierra Leone officially reported to the World Health Organization. The overall mean CFR was 62.9% (95% CI: 61.9% to 64.0%) among confirmed cases with recorded clinical outcomes. Age was the most important modifier of survival probabilities, but country, stage of the epidemic and whether patients were hospitalized also played roles. We developed a statistical analysis to detect outliers in CFR between districts of residence and treatment centres (TCs), adjusting for known factors influencing survival and identified eight districts and three TCs with a CFR significantly different from the average. From the current dataset, we cannot determine whether the observed variation in CFR seen by district or treatment centre reflects real differences in survival, related to the quality of care or other factors or was caused by differences in reporting practices or case ascertainment.

This article is part of the themed issue ‘The 2013–2016 West African Ebola epidemic: data, decision-making and disease control’.

Insights from clinical research completed during the west Africa Ebola virus disease epidemic

The west Africa Ebola virus disease (EVD) epidemic was extraordinary in scale. Now that the epidemic has ended, it is a relevant time to examine published studies with direct relevance to clinical care and, more broadly, to examine the implications of the clinical research response mounted. Clinically relevant research includes literature detailing risk factors for and clinical manifestations of EVD, laboratory and other investigation findings in patients, experimental vaccine and therapeutic clinical trials, and analyses of survivor syndrome. In this Review, we discuss new insights from patient-oriented research completed during the west Africa epidemic, identify ongoing knowledge gaps, and suggest priorities for future research.

Ebola virus disease in children during the 2014-2015 epidemic in Guinea: a nationwide cohort study

The most recent epidemic of Ebola virus disease (EVD) has resulted in more than 11,000 deaths in West Africa. It has threatened child health in the affected countries, including Guinea. This nationwide retrospective cohort study included all children under 20 years of age with laboratory-confirmed EVD in Guinea during the 2014-2015 Ebola outbreak for analysis. Of 8,448 children with probable or suspected EVD, 695 cases were laboratory-confirmed EVD. The overall case fatality rate (CFR) was 62.9%. Pediatric patients with younger age had a significantly higher rate of death (adjusted OR = 0.995; 95%CI = 0.990-1.000; p = 0.046), with the highest CFR of 82.9% in children aged less than 5 years. Fever (91%), fatigue (87%), and gastrointestinal signs and symptoms (70%) were common clinical features on admission of the pediatric patients, while bleeding signs were not occurring often (24%). None of clinical features and epidemiologic risk factors for Ebola were associated with mortality outcome in our cohort study.

CONCLUSION

EVD is a major threat to child health, especially among children under 5 years of age. To date, none of demographic and clinical features, except younger age, have been consistently shown to affect mortality outcome in children infected with Ebola virus. What is Known: • The 2014-2015 West Africa Ebola epidemic is the largest and most widespread outbreak of Ebola virus disease (EVD) in history, with more than 11,000 deaths in Guinea, Liberia, and Sierra Leone. • During ongoing outbreak investigations, it is suggested that young children aged less than 5 years are particularly vulnerable and highly susceptible to death. What is New: • Demographic and clinical characteristics of the nationwide cohort of pediatric patients with laboratory-confirmed EVD in Guinea are reported. • The results confirm the high rate of death among EVD children under 5 years of age, while none of demographic and clinical features, except younger age, could serve as a predictor of mortality outcome in pediatric patients with EVD.

Asymptomatic infection and unrecognised Ebola virus disease in Ebola-affected households in Sierra Leone: a cross-sectional study using a new non-invasive assay for antibodies to Ebola virus

BACKGROUND

The frequency of asymptomatic infection with Ebola virus is unclear: previous estimates vary and there is no standard test. Asymptomatic infection with Ebola virus could contribute to population immunity, reducing spread. If people with asymptomatic infection are infectious it could explain re-emergences of Ebola virus disease (EVD) without known contact.

METHODS

We validated a new oral fluid anti-glycoprotein IgG capture assay among survivors from Kerry Town Ebola Treatment Centre and controls from communities unaffected by EVD in Sierra Leone. We then assessed the seroprevalence of antibodies to Ebola virus in a cross-sectional study of household contacts of the survivors. All household members were interviewed. Two reactive tests were required for a positive result, with a third test to resolve any discrepancies.

FINDINGS

The assay had a specificity of 100% (95% CI 98·9-100; 339 of 339 controls tested negative) and sensitivity of 95·9% (89·8-98·9; 93 of 97 PCR-confirmed survivors tested positive). Of household contacts not diagnosed with EVD, 47·6% (229 of 481) had high level exposure (direct contact with a corpse, body fluids, or a case with diarrhoea, vomiting, or bleeding). Among the contacts, 12·0% (95% CI 6·1-20·4; 11 of 92) with symptoms at the time other household members had EVD, and 2·6% (1·2-4·7; 10 of 388) with no symptoms tested positive. Among asymptomatic contacts, seropositivity was weakly correlated with exposure level.

INTERPRETATION

This new highly specific and sensitive assay showed asymptomatic infection with Ebola virus was uncommon despite high exposure. The low prevalence suggests asymptomatic infection contributes little to herd immunity in Ebola, and even if infectious, would account for few transmissions.

FUNDING

Wellcome Trust ERAES Programme, Save the Children.

Characteristics and Outcomes of Pediatric Patients With Ebola Virus Disease Admitted to Treatment Units in Liberia and Sierra Leone: A Retrospective Cohort Study

BACKGROUND

The clinical and virologic characteristics of Ebola virus disease (EVD) in children have not been thoroughly documented.

METHODS

Consecutive children aged <18 years with real-time polymerase chain reaction (RT-PCR)-confirmed EVD were enrolled retrospectively in 5 Ebola treatment units in Liberia and Sierra Leone in 2014/2015. Data collection and medical management were based on standardized International Medical Corps protocols. We performed descriptive statistics, multivariate logistic regression, and Kaplan-Meier survival analyses.

RESULTS

Of 122 children enrolled, the median age was 7 years and one-third were aged <5 years. The female-to-male ratio was 1.3. The most common clinical features at triage and during hospitalization were fever, weakness, anorexia, and diarrhea, although 21% of patients were initially afebrile and 6 patients remained afebrile. Bleeding was rare at presentation (5%) and manifested subsequently in fewer than 50%. The overall case fatality rate was 57%. Factors associated with death in bivariate analyses were age <5 years, bleeding at any time during hospitalization, and high viral load. After adjustment with logistic regression modeling, the odds of death were 14.8-fold higher if patients were aged <5 years, 5-fold higher if the patient had any evidence of bleeding, and 5.2-fold higher if EVD RT-PCR cycle threshold value was ≤20. Plasmodium parasitemia had no impact on EVD outcomes.

CONCLUSIONS

Age <5 years, bleeding, and high viral loads were poor prognostic indicators of children with EVD. Research to understand mechanisms of these risk factors and the impact of dehydration and electrolyte imbalance will improve health outcomes.