International Congress on Targeting Ebola: 28-29 May 2015, Pasteur Institute, Paris.

Introduction

The International Congress on Targeting Ebola 2015 was held on 28–29 May 2015 at the Pasteur Institute in Paris ( www.targeting-ebola.com). The meeting was organised in partnership with the COPED of the French Academy of Sciences, the French Task Force Group for Ebola, the Pasteur Institute and the Task Force for Infectious Diseases. Publication of a summary of the meeting by the organisers is anticipated in an open-access journal. This paper aims to provide a brief overview of the main discussion points during the meeting.

This meeting brought together more than 300 experts in the field of ebola virus disease (EVD) from Europe, Africa, Asia and the US to discuss advances in combatting the virus. Their expertise encompassed infectious diseases, basic science, epidemiology, anthropology, virology, immunology, and included representatives from industry (both diagnostics and therapeutics), non-governmental organisations (NGOs) such as Médecins Sans Frontières (MSF), funding agencies such as the Gates Foundation and Fondation Mérieux, and the World Health Organization (WHO). The meeting aimed to cover diverse topics including viral pathogenesis, virus–host interactions, epidemiology, cultural aspects of the disease, diagnostic tools, treatment protocols, vaccines and operational research.

Conference discussion

The index case was thought to arise on 6 December 2013. The WHO was notified on 23 March 2014 of an EVD outbreak in Guinea, with rapid spread to Liberia and Sierra Leone by May 2014. On 8 August 2014 it was declared a Public Health Emergency of International Concern (PHEIC). Peak transmission occurred during August and September 2014, with a reported case fatality rate of up to 70% [1]. By the end of May 2015 over 27,000 cases and more than 12,000 deaths had been reported in Sierra Leone, Liberia and Guinea. Following the conference close, by the end of August 2015, Liberia and Sierra Leone had no reported cases in the preceding weeks, with limited onwards transmission in Guinea [2].

At the time of the conference the countries affected by the West African outbreak included the Democratic Republic of Congo (DRC), Guinea, Liberia, Mali, Nigeria, Senegal, Sierra Leone, Spain, the United Kingdom and the United States. The outbreak was unprecedented in terms of its scale, severity and complexity [3]. A strong emphasis throughout the meeting was placed on the need to develop strategies to ensure that any future outbreak did not escalate to this level, through both scientific and community engagement. The need for better diagnostics, therapeutics and vaccines for all highly pathogenic viruses, together with regular international monitoring, was repeatedly mentioned. Reflections were made on previous outbreaks.

Two of the ‘founding fathers’ of EVD care, Professors Peter Piot and Jean-Jacques Muyembe-Tamfum, highlighted key, recurrent messages throughout the meeting. Professor Piot, one of the discoverers of the Ebola virus, described a recent return to Yambuku in the DRC, the site of the first EVD outbreak in 1976. The current state of the healthcare infrastructure did not reflect the many promises of future investments made at the time of the outbreak, a poignant reminder that we must not assume that current promises of investment will always materialise.

Professor Muyembe-Tamfum, a microbiologist with four decades of EVD experience, warned how outbreaks have become more frequent since 2012 in the DRC, both with the Zaire ebolavirus (EBOV) strain now seen in West Africa, and the Bundibuyo ebolavirus (BDBV). He stressed that a community approach was fundamental for control measures, with the need for dialogue and negotiation with communities paramount. Despite the DRC's long-standing expertise and vigilance, developed through managing EVD outbreaks, early recognition remains challenging with a wide differential diagnosis including malaria and typhoid fever, and outbreaks in remote areas with poor laboratory diagnostics.

Dr Sylvie Briand, the Director of Pandemic and Epidemic Diseases for the WHO, highlighted that it was fundamental to strengthen the local capacities of countries to respond to future outbreaks to ensure that the International Health Regulations could be delivered. WHO interventions have included technical support and coordination with experts in high-transmission countries, pre-deployment training of over 1500 people, with 732 staff deployed in 77 field sites by April 2015. This significant experience will be of great future benefit if harnessed appropriately. She warned that we must not be complacent and must heed lessons from the pandemic H1N1 influenza, which spread to every continent within 9 weeks [4].

Combined, these reflections framed the intense discussion over the two days of the meeting, which included oral and poster presentations by an array of experts in the field. The key messages from this collective experience can be thematically grouped into the following points.

The delay in global response was unacceptable

However, there has subsequently been an unprecedented international response that has created opportunities to collectively improve how we deal with global infectious disease crises. We must engage with these discussions to ensure lessons are learned. Political commitment, national coordination, appropriate financing, global governance and support from international partners are needed. We must be poised to deliver a rapid response effectively next time.

Future outbreaks are almost inevitable

This was highlighted by the seventh DRC outbreak in the Boende district, where the index case was a pregnant woman and the source of infection a dead monkey found in the forest by her husband. How to prevent animal-to-human transmission in rural areas where consumption of bush meat and hunting activities are common is a challenging reality for disease control. Mapping of the zoonotic niche is greatly needed to identify current and new at-risk regions, particularly given rapidly changing population growth, and urban and non-urban increases in mobility. Emphasis was placed on the intense urban transmission including in all three affected capital cities.

Rapid diagnostic tests are key, along with back-up laboratory support

Novel ways of providing rapid, highly sensitive and specific diagnosis such as point-of-care diagnostic tests (antigen-based lateral flow assays and RT-LAMP) to EVD-prone areas in resource-limited countries are urgently needed. Alternative methods of sample collection such as capillary blood, oral swabs and urine collection should be utilised, alongside new platforms such as cards and microtubes. Mobile laboratories for confirmatory testing and supportive pathology services, and deep sequencing to identify reintroductions of virus and mapping of viral evolution for assessing chains of transmission are also key priorities. Innovative, combined research in this area can also help address future investments in outbreak control.

Multidisciplinary approaches to outbreak control are vital

EVD outbreaks threaten both society and the individual. They generate fear through its spread by practices normally associated with acts of love and care, with significant family and nosocomial transmission. This outbreak arose in a region with inadequate health systems following years of civil war, with ongoing issues of mistrust. EVD reinforces existing stereotypes and prejudices (rural versus urban, for example). Tensions between population health and individual care further exacerbate anxieties: these have framed the early local responses to the epidemic. Ebola Treatment Centres (ETCs) may also have exacerbated tensions, as the care is conducted unseen, inside, by masked individuals. The fundamental role of communities in an effective response to any epidemic has to take into account the particular socio-cultural characteristics of the communities involved. Therefore, we must include within the traditional paradigm of EVD interventions, such as contact tracing, ETCs and supervised burial, community engagement as a paramount feature.

The frailty of healthcare in West Africa must not be ignored

The outbreak has taken a very heavy toll on local healthcare with over 850 confirmed infections in healthcare workers and more than 500 deaths in Guinea, Liberia and Sierra Leone by May 2015. This is set against a background of poorly resourced and supported systems, both in terms of human resources, logistics and infrastructure. Healthcare facilities and staff must be protected, and investments made to strengthen systems. The recent outbreak has made the affected countries even more vulnerable to new waves of diseases, with a significant lack of basic medical care during the period of highest transmission. We must ensure that appropriate support is in place to rebuild and strengthen healthcare infrastructure.

We need to understand the disease better

A significant insight into laboratory markers associated with prognosis has been gained, in particular the deleterious impact of high initial viral load and abnormal biochemistry. This is an important step to guide treatment and clinical trials, but we must further elucidate host–virus interactions. Major steps include a better understanding of vascular cytotoxicity and injury due to EBOV glycoproteins, novel receptors required for viral replication and pathogenesis, interferon antagonism, and the viral nucleocapsid. Novel animal models are being developed to inform how non-human primate and small animal research can translate into improved human outcomes. There is considerable ongoing research to determine the clinical, including long-term, sequelae from surviving EVD in individuals, and how best they should be managed.

Novel treatments and vaccines are key

At the time of the conference there were no results from a randomised trial to guide therapy or to provide a prophylactic vaccine. Therefore, there is an urgent requirement for research to continue, and for developing the framework for conducting appropriate clinical and operational research. There are presently several vaccine candidates for the prevention of EVD but at the time of the meeting none had proven efficacy – recently a novel cluster-randomised ring vaccination trial has demonstrated Phase III efficacy of the rVSV-ZEBOV vaccine [5]. Available potential drugs for EVD treatment include favipiravir and brincidofovir, monoclonal antibody combinations such as ZMapp on its own or in combination, novel compounds such as TKM-Ebola, and convalescent plasma. The relative benefit of each of these remains unclear. There is an ongoing debate regarding the ethics of randomisation in clinical trials during the peak of an escalating epidemic with high mortality. The coordination of such trials in the face of decreasing numbers of new patients highlights the complexities of any field research, and how advanced discussions must happen before any future outbreak. The use of non-controlled trials and other strategies needs to be addressed and codified. Organisations such as MSF have now developed considerable experience in clinical trials, but involvement of the NGO community in future research needs to be strengthened. An emphasis was put on the need to develop local biotechnologies and research capacity, for example to conduct plasmapheresis and enable fractionation of convalescent plasma into gamma globulin.

How much risk remains in the countries declared disease free?

There is the possibility of long-term carriage of viable virus in the seminal fluid of survivors, with a likely sexual contact responsible for reintroduction of EVD into Liberia in May 2015 [6]. Seminal fluid remains culture positive for many months, and given the many thousands of surviving men, with uncertainty as to the upper end of such viral carriage, this has serious implications for the potential for disease reintroduction. Understanding and assessing this risk are key research questions going forward. There is also an important role for Ebola survivors in ongoing community engagement.

Looking to the future

Underpinning these future challenges was the recognition of the achievements that have been made during the 2014–2015 West African outbreak. Scientific advances, significant commitment from national and international agencies, and developments in local capacity in the affected countries have occurred. There are encouraging, ongoing basic science research innovations, developments in translational, bench-to-bedside laboratory and clinical science, and an improved understanding of how a multi-faceted disease response can best be constructed.

The sacrifice of local healthcare workers who have died caring for others was both mourned and celebrated, with a collective will going forward to tackle the challenges identified, and renew efforts on the ‘Road to Zero’. Leadership in policy-making, global governance, investments in the detection of serious pathogens, coupled with epidemiological surveillance and detailed analysis of what works, and importantly, what does not work, are key in combatting the ongoing threat of EVD.