Estimating the impact of violent events on transmission in Ebola virus disease outbreak, Democratic Republic of the Congo, 2018-2019

Ebola Virus Disease Outbreaks: Lessons Learned From Past and Facing Future Challenges

INTRODUCTION

The purpose of this review is to examine African Ebola outbreaks from their first discovery to the present, to determine how the medical and public health response has changed and identify the causes for those changes. We sought to describe what is now known about the epidemiology and spread of Ebola virus disease (EVD) from the significant outbreaks that have occurred and outbreak control methods applied under often challenging circumstances. Given the substantial role that the U.S. Government and the U.S. DoD have played in the 2014 to 2016 West African Ebola outbreak, the role of the DoD and the U.S. Africa Command in controlling EVD is described.

MATERIALS AND METHODS

A descriptive method design was used to collect and analyze all available Ebola outbreak literature using the PubMed database. An initial literature search was conducted by searching for, obtaining, and reading original source articles on all major global Ebola outbreaks. To conduct a focused search, we used initial search terms "Ebola outbreak," "Ebola virus disease," "Ebola response," "Ebola countermeasures," and also included each country's name where Ebola cases are known to have occurred. From the 4,673 unique articles obtained from this search and subsequent article title review, 307 articles were identified for potential inclusion. Following abstract and article review, 45 original source articles were used to compile the history of significant Ebola outbreaks. From this compilation, articles focused on each respective subsection of this review to delineate and describe the history of EVD and response, identifying fundamental changes, were obtained and incorporated.

RESULTS

We present known Ebola virus and disease attributes, including a general description, seasonality and location, transmission capacity, clinical symptoms, surveillance, virology, historical EVD outbreaks and response, international support for Ebola outbreak response, U.S. DoD support, medical countermeasures supporting outbreak response, remaining gaps to include policy limitations, regional instability, climate change, migration, and urbanization, public health education and infrastructure, and virus persistence and public awareness.

CONCLUSIONS

The health and societal impacts of EVD on Africa has been far-reaching, with about 35,000 cases and over 15,000 deaths, with small numbers of cases spreading globally. However, the history of combatting EVD reveals that there is considerable hope for African nations to quickly and successfully respond to Ebola outbreaks, through use of endemic resources including Africa CDC and African Partner Outbreak Response Alliance and the U.S. Africa Command with greater DoD reachback. Although there remains much to be learned about the Ebola virus and EVD including whether the potential for novel strains to become deadly emerging infections, invaluable vaccines, antivirals, and public health measures are now part of the resources that can be used to combat this disease.

The cost of public health interventions to respond to the 10th Ebola outbreak in the Democratic Republic of the Congo

The 10th Ebola virus disease (EVD) outbreak in the Democratic Republic of the Congo (DRC) drew substantial attention from the international community, which in turn invested more than US$1 billion in EVD control over two years (2018-2020). This is the first EVD outbreak to take place in a conflict area, which led to a shift in strategy from a pure public health response (PHR) to a multisectoral humanitarian response. A wide range of disease control and mitigation activities were implemented and were outlined in the five budgeted Strategic Response Plans used throughout the 26 months. This study used the budget/expenditure and output indicators for disease control and mitigation interventions compiled by the government of DRC and development and humanitarian partners to estimate unit costs of key Ebola control interventions. Of all the investment in EVD control, 68% was spent on PHR. The remaining 32% covered security, community support interventions for the PHR. The disbursement for the public health pillar was distributed as follows: (1) coordination (18.8%), (2), clinical management of EVD cases (18.4%), (3) surveillance and vaccination (15.9%), (4) infection prevention and control/WASH (13.8%) and (5) risk communication (13.7%). The unit costs of key EVD control interventions were as follows: US$66 182 for maintaining a rapid response team per month, US$4435 for contact tracing and surveillance per identified EVD case, US$1464 for EVD treatment per case, US$59.4 per EVD laboratory test, US$120.7 per vaccinated individual against EVD and US$175.0 for mental health and psychosocial support per beneficiary. The estimated unit costs of key EVD disease control interventions provide crucial information for future infectious disease control planning and budgeting, as well as prioritisation of disease control interventions.

Identifying Paucisymptomatic or Asymptomatic and Unrecognized Ebola Virus Disease Among Close Contacts Based on Exposure Risk Assessments and Screening Algorithms

BACKGROUND

There is limited evidence to evaluate screening algorithms with rapid antigen testing and exposure assessments as identification strategies for paucisymptomatic or asymptomatic Ebola virus (EBOV) infection and unrecognized EBOV disease (EVD).

METHODS

We used serostatus and self-reported postexposure symptoms from a cohort study to classify contact-participants as having no infection, paucisymptomatic or asymptomatic infection, or unrecognized EVD. Exposure risk was categorized as low, intermediate, or high. We created hypothetical scenarios to evaluate the World Health Organization (WHO) case definition with or without rapid diagnostic testing (RDT) or exposure assessments.

RESULTS

This analysis included 990 EVD survivors and 1909 contacts, of whom 115 (6%) had paucisymptomatic or asymptomatic EBOV infection, 107 (6%) had unrecognized EVD, and 1687 (88%) were uninfected. High-risk exposures were drivers of unrecognized EVD (adjusted odds ratio, 3.5 [95% confidence interval, 2.4-4.9]). To identify contacts with unrecognized EVD who test negative by the WHO case definition, the sensitivity was 96% with RDT (95% confidence interval, 91%-99%), 87% with high-risk exposure (82%-92%), and 97% with intermediate- to high-risk exposures (93%-99%). The proportion of false-positives was 2% with RDT and 53%-93% with intermediate- and/or high-risk exposures.

CONCLUSION

We demonstrated the utility and trade-offs of sequential screening algorithms with RDT or exposure risk assessments as identification strategies for contacts with unrecognized EVD.

Analysis of the management of the tenth Ebola virus disease outbreak in the Democratic Republic of Congo: developing a multidisciplinary response model to strengthen the healthcare system during disease outbreaks

The declaration of any public health emergency in the Democratic Republic of Congo (DRC) is usually followed by the provision of technical and organizational support from international organizations, which build a parallel and short-time healthcare emergency response centered on preventing the extension of health emergencies across the countries and over the world. Previous Ebola virus disease (EVD) outbreaks have highlighted the need to reinforce the healthcare sector in different countries.Based on the difficulty to implement the International Health Regulations (2005) to the local level of affected countries including the DRC, this paper proposes a multidisciplinary model based on the health zones through the strengthening of preparedness and response structures to public health emergencies vis-à-vis the existing weak health systems existing in DRC. A commitment to integrating the emergency response in the existing health system should work to reduce the tension that exists between local recruitment and its impact on the quality of daily healthcare in the region affected by EVD outbreak on one hand, and the involvement of international recruitment and its impact on the trust of the population on the emergency response on the other. This paper highlights the provision of a local healthcare workforce skilled to treat infectious diseases, the compulsory implementation of training programs focused on the emergency response in countries commonly affected by EVD outbreaks including the DRC. These innovations should reduce the burden of health problems prior to and in the aftermath of any public health emergency in DRC hence increasing the wellbeing of the community, especially the vulnerable people as well as the availability of trained healthcare providers able to early recognize and treat EVD.

Responding to the 2018-2020 Ebola Virus Outbreak in the Democratic Republic of the Congo: Rethinking Humanitarian Approaches

The Democratic Republic of Congo (DRC) presents a challenging context in which to respond to public health crises. Its 2018-2020 Ebola outbreak was the second largest in history. Lessons were known from the previous West African outbreak. Chief among these was the recognition that local action and involvement are key to establishing effective epidemic-response. It remains unclear whether and how this was achieved in DRC's Ebola response. Additionally, there is a lack of scholarship on how to build resilience (the ability to adapt or transform under pressure) in crisis-response. In this article, we critically review literature to examine evidence on whether and how communities were involved, trust built, and resilience strengthened through adaptation or transformation of DRC's 2018-2020 Ebola response measures. Overall, we found limited evidence that the response adapted to engage and involve local actors and institutions or respond to locally expressed concerns. When adaptations occurred, they were shaped by national and international actors rather than enabling local actors to develop locally trusted initiatives. Communities were "engaged" to understand their perceptions but were not involved in decision-making or shaping responses. Few studies documented how trust was built or analyzed power dynamics between different groups in DRC. Yet, both these elements appear to be critical in building effective, resilient responses. These failures occurred because there was no willingness by the national government or international agencies to concede decision-making power to local people. Emergency humanitarian response is entrenched in highly medicalized, military style command and control approaches which have no space for decentralizing decision-making to "non-experts". To transform humanitarian responses, international responders can no longer be regarded as "experts" who own the knowledge and control the response. To successfully tackle future humanitarian crises requires a transformation of international humanitarian and emergency response systems such that they are led, or shaped, through inclusive, equitable collaboration with local actors.

Bayesian spatial modelling of Ebola outbreaks in Democratic Republic of Congo through the INLA-SPDE approach

Ebola virus (EBV) disease is a globally acknowledged public health emergency, endemic in the west and equatorial Africa. To understand the epidemiology especially the dynamic pattern of EBV disease, we analyse the EBV case notification data for confirmed cases and reported deaths of the ongoing outbreak in the Democratic Republic of Congo (DRC) between 2018 and 2019, and examined the impact of reported violence on the spread of the virus. Using fully Bayesian geo-statistical analysis through stochastic partial differential equations (SPDE) allows us to quantify the spatial patterns at every point of the spatial domain. Parameter estimation was based on the integrated nested Laplace approximation (INLA). Our findings revealed a positive association between violent events in the affected areas and the reported EBV cases (posterior mean = 0.024, 95% CI: 0.005, 0.045) and deaths (posterior mean = 0.022, 95% CI: 0.005, 0.041). Translating to an increase of 2.4% and 2.2% in the relative risks of EBV cases and deaths associated with a unit increase in violent events (one additional Ebola case is associated with an average of 45 violent events). We also observed clusters of EBV cases and deaths spread to neighbouring locations in similar manners. Findings from the study are therefore useful for hot spot identification, location-specific disease surveillance and intervention.

Identification and evaluation of epidemic prediction and forecasting reporting guidelines: A systematic review and a call for action

INTRODUCTION

High quality epidemic forecasting and prediction are critical to support response to local, regional and global infectious disease threats. Other fields of biomedical research use consensus reporting guidelines to ensure standardization and quality of research practice among researchers, and to provide a framework for end-users to interpret the validity of study results. The purpose of this study was to determine whether guidelines exist specifically for epidemic forecast and prediction publications.

METHODS

We undertook a formal systematic review to identify and evaluate any published infectious disease epidemic forecasting and prediction reporting guidelines. This review leveraged a team of 18 investigators from US Government and academic sectors.

RESULTS

A literature database search through May 26, 2019, identified 1467 publications (MEDLINE n = 584, EMBASE n = 883), and a grey-literature review identified a further 407 publications, yielding a total 1777 unique publications. A paired-reviewer system screened in 25 potentially eligible publications, of which two were ultimately deemed eligible. A qualitative review of these two published reporting guidelines indicated that neither were specific for epidemic forecasting and prediction, although they described reporting items which may be relevant to epidemic forecasting and prediction studies.

CONCLUSIONS

This systematic review confirms that no specific guidelines have been published to standardize the reporting of epidemic forecasting and prediction studies. These findings underscore the need to develop such reporting guidelines in order to improve the transparency, quality and implementation of epidemic forecasting and prediction research in operational public health.

The Impact of Different Types of Violence on Ebola Virus Transmission During the 2018-2020 Outbreak in the Democratic Republic of the Congo

BACKGROUND

Our understanding of the different effects of targeted versus nontargeted violence on Ebola virus (EBOV) transmission in Democratic Republic of the Congo (DRC) is limited.

METHODS

We used time-series data of case counts to compare individuals in Ebola-affected health zones in DRC, April 2018-August 2019. Exposure was number of violent events per health zone, categorized into Ebola-targeted or Ebola-untargeted, and into civilian-induced, (para)military/political, or protests. Outcome was estimated daily reproduction number (Rt) by health zone. We fit linear time-series regression to model the relationship.

RESULTS

Average Rt was 1.06 (95% confidence interval [CI], 1.02-1.11). A mean of 2.92 violent events resulted in cumulative absolute increase in Rt of 0.10 (95% CI, .05-.15). More violent events increased EBOV transmission (P = .03). Considering violent events in the 95th percentile over a 21-day interval and its relative impact on Rt, Ebola-targeted events corresponded to Rt of 1.52 (95% CI, 1.30-1.74), while civilian-induced events corresponded to Rt of 1.43 (95% CI, 1.21-1.35). Untargeted events corresponded to Rt of 1.18 (95% CI, 1.02-1.35); among these, militia/political or ville morte events increased transmission.

CONCLUSIONS

Ebola-targeted violence, primarily driven by civilian-induced events, had the largest impact on EBOV transmission.

The cost of insecurity: from flare-up to control of a major Ebola virus disease hotspot during the outbreak in the Democratic Republic of the Congo, 2019

The ongoing Ebola outbreak in the eastern Democratic Republic of the Congo is facing unprecedented levels of insecurity and violence. We evaluate the likely impact in terms of added transmissibility and cases of major security incidents in the Butembo coordination hub. We also show that despite this additional burden, an adapted response strategy involving enlarged ring vaccination around clusters of cases and enhanced community engagement managed to bring this main hotspot under control.

Recent successes in therapeutics for Ebola virus disease: no time for complacency

The PALM trial in the Democratic Republic of the Congo identified a statistically significant survival benefit for two monoclonal antibody-based therapeutics in the treatment of acute Ebola virus disease; however, substantial gaps remain in improving the outcomes of acute Ebola virus disease and for the survivors. Ongoing efforts are needed to develop more effective strategies, particularly for individuals with severe disease, for prevention and treatment of viral persistence in immune-privileged sites, for optimisation of post-exposure prophylaxis, and to increase therapeutic breadth. As antibody-based approaches are identified and advanced, promising small-molecule antivirals currently in clinical stage development should continue to be evaluated for filovirus diseases, with consideration of their added value in combination approaches with bundled supportive care, their penetration in tissues of interest, the absence of interaction with glycoprotein-based vaccines, and filoviral breadth.

Multi-model forecasts of the ongoing Ebola epidemic in the Democratic Republic of Congo, March-October 2019

The 2018–2020 Ebola outbreak in the Democratic Republic of the Congo is the first to occur in an armed conflict zone. The resulting impact on population movement, treatment centres and surveillance has created an unprecedented challenge for real-time epidemic forecasting. Most standard mathematical models cannot capture the observed incidence trajectory when it deviates from a traditional epidemic logistic curve. We fit seven dynamic models of increasing complexity to the incidence data published in the World Health Organization Situation Reports, after adjusting for reporting delays. These models include a simple logistic model, a Richards model, an endemic Richards model, a double logistic growth model, a multi-model approach and two sub-epidemic models. We analyse model fit to the data and compare real-time forecasts throughout the ongoing epidemic across 29 weeks from 11 March to 23 September 2019. We observe that the modest extensions presented allow for capturing a wide range of epidemic behaviour. The multi-model approach yields the most reliable forecasts on average for this application, and the presented extensions improve model flexibility and forecasting accuracy, even in the context of limited epidemiological data.

What did we learn from preparing for cross-border transmission of Ebola virus disease into a complex humanitarian setting - The Republic of South Sudan?

Background

Following the West Africa Ebola virus disease (EVD) outbreak (2013–2016), WHO developed a preparedness checklist for its member states. This checklist is currently being applied for the first time on a large and systematic scale to prepare for the cross border importation of the ongoing EVD outbreak in the Democratic Republic of Congo hence the need to document the lessons learnt from this experience. This is more pertinent considering the complex humanitarian context and weak health system under which some of the countries such as the Republic of South Sudan are implementing their EVD preparedness interventions.

Main text

We identified four main lessons from the ongoing EVD preparedness efforts in the Republic South Sudan. First, EVD preparedness is possible in complex humanitarian settings such as the Republic of South Sudan by using a longer-term health system strengthening approach. Second, the Republic of South Sudan is at risk of both domestic and cross border transmission of EVD and several other infectious disease outbreaks hence the need for an integrated and sustainable approach to outbreak preparedness in the country. Third, a phased and well-prioritized approach is required for EVD preparedness in complex humanitarian settings given the costs associated with preparedness and the difficulties in the accurate prediction of outbreaks in such settings. Fourth, EVD preparedness in complex humanitarian settings is a massive undertaking that requires effective and decentralized coordination.

Conclusion

Despite a very challenging context, the Republic of South Sudan made significant progress in its EVD preparedness drive demonstrating that it is possible to rapidly scale up preparedness efforts in complex humanitarian contexts if appropriate and context-specific approaches are used. Further research, systematic reviews and evaluation of the ongoing preparedness efforts are required to ensure comprehensive documentation and application of the lessons learnt for future EVD outbreak preparedness and response efforts.

Ebola virus disease

Ebola virus disease (EVD) is a severe and frequently lethal disease caused by Ebola virus (EBOV). EVD outbreaks typically start from a single case of probable zoonotic transmission, followed by human-to-human transmission via direct contact or contact with infected bodily fluids or contaminated fomites. EVD has a high case-fatality rate; it is characterized by fever, gastrointestinal signs and multiple organ dysfunction syndrome. Diagnosis requires a combination of case definition and laboratory tests, typically real-time reverse transcription PCR to detect viral RNA or rapid diagnostic tests based on immunoassays to detect EBOV antigens. Recent advances in medical countermeasure research resulted in the recent approval of an EBOV-targeted vaccine by European and US regulatory agencies. The results of a randomized clinical trial of investigational therapeutics for EVD demonstrated survival benefits from two monoclonal antibody products targeting the EBOV membrane glycoprotein. New observations emerging from the unprecedented 2013-2016 Western African EVD outbreak (the largest in history) and the ongoing EVD outbreak in the Democratic Republic of the Congo have substantially improved the understanding of EVD and viral persistence in survivors of EVD, resulting in new strategies toward prevention of infection and optimization of clinical management, acute illness outcomes and attendance to the clinical care needs of patients.

The 2018/19 Ebola epidemic the Democratic Republic of the Congo (DRC): epidemiology, outbreak control, and conflict

The Democratic Republic of Congo (DRC) (formerly Zaire) was the location of the first Ebola outbreak, in 1976, and since then there have been a total of ten outbreaks in different parts of the country. The current outbreak, the first in eastern DRC (North Kivu and Ituri provinces), began in July 2018, and by December 2019, there had been 3262 cases and 2232 deaths. Within weeks of the first reported cases, the World Health Organisation (WHO) and the DRC Ministry of Health (MOH) initiated a major response programme, with laboratory support, international agencies providing personnel, and material resources. Unlike previous Ebola outbreaks, including the west Africa epidemic, a proven vaccine, and trial therapeutic agents have been available as part of the outbreak response. Two therapeutic agents, mAb114 and REGN-EB3, both monoclonal antibody derived, have shown case fatality rates (CFR) of around 30%, compared to the overall of 66%. Despite these positive interventions, the outbreak has continued for eighteen months. Underlying the outbreak response has been a high number of violent incidents by local militias, and community mistrust and lack of involvement that has hampered many aspects of the response programme. As a result, many cases are not reported early and not transferred to treatment centres, deaths and increased transmission occur in the community, and the response programme is reaching only a proportion of the cases. New strategies to improve community participation, and integrate the Ebola response into the existing health structure are planned to improve the programme effectiveness.

Recurrent Ebolavirus disease in the Democratic Republic of Congo: update and challenges

The current Ebolavirus disease (EVD) outbreak in the provinces of North Kivu and Ituri is the tenth outbreak affecting the Democratic Republic of Congo (DRC); the first outbreak occurring in a war context, and the second most deadly Ebolavirus outbreak on record following the 2014 outbreak in West Africa. The DRC government's response consisted of applying a package of interventions including detection and rapid isolation of cases, contact tracing, population mapping, and identification of high-risk areas to inform a coordinated effort. The coordinated effort was to screen, ring vaccinate, and conduct laboratory diagnoses using GeneXpert (Cepheid) polymerase chain reaction. The effort also included ensuring safe and dignified burials and promoting risk communication, community engagement, and social mobilization. Following the adoption of the “Monitored Emergency Use of Unregistered Products Protocol,” a randomized controlled trial of four investigational treatments (mAb114, ZMapp, and REGN-EB3 and Remdesivir) was carried out with all consenting patients with laboratory-confirmed EVD. REGN-EB3 and mAb114 showed promise as treatments for EVD. In addition, one investigational vaccine (rVSV-ZEBOV-GP) was used first, followed by a second prophylactic vaccine (Ad26.ZEBOV/MVA-BN-Filo) to reinforce the prevention. Although the provision of clinical supportive care remains the cornerstone of EVD outbreak management, the DRC response faced daunting challenges including general insecurity, violence and community resistance, appalling poverty, and entrenched distrust of authority. Ebolavirus remains a public health threat. A fully curative treatment is unlikely to be a game-changer given the settings of transmission, zoonotic nature, limits of effectiveness of any therapeutic intervention, and timing of presentation.

Spatial variability in the reproduction number of Ebola virus disease, Democratic Republic of the Congo, January-September 2019

The ongoing Ebola virus disease epidemic (August 2018─October 2019) in the Democratic Republic of the Congo, has been exacerbated by deliberate attacks on healthcare workers despite vaccination efforts. Using a mathematical/statistical modelling framework, we present the quantified effective reproduction number (R_t) at national and regional levels as at 29 September. The weekly trend in R_t displays fluctuations while our recent national-level R_t falls slightly above 1.0 with substantial uncertainty, which suggests improvements in epidemic control.