David L. Heymann

The Reemergence of Ebola Hemorrhagic Fever, Democratic Republic of the Congo, 1995

In May 1995, an international team characterized and contained an outbreak of Ebola hemorrhagic fever (EHF) in Kikwit, Democratic Republic of the Congo. Active surveillance was instituted using several methods, including house-to-house search, review of hospital and dispensary logs, interview of health care personnel, retrospective contact tracing, and direct follow-up of suspect cases. In the field, a clinical case was defined as fever and hemorrhagic signs, fever plus contact with a case-patient, or fever plus at least 3 of 10 symptoms. A total of 315 cases of EHF, with an 81% case fatality, were identified, excluding 10 clinical cases with negative laboratory results. The earliest documented case-patient had onset on 6 January, and the last case-patient died on 16 July. Eighty cases (25%) occurred among health care workers. Two individuals may have been the source of infection for >50 cases. The outbreak was terminated by the initiation of barrier-nursing techniques, health education efforts, and rapid identification of cases.

Communicable diseases in complex emergencies: impact and challenges

Communicable diseases, alone or in combination with malnutrition, account for most deaths in complex emergencies. Factors promoting disease transmission interact synergistically leading to high incidence rates of diarrhoea, respiratory infection, malaria, and measles. This excess morbidity and mortality is avoidable as effective interventions are available. Adequate shelter, water, food, and sanitation linked to effective case management, immunisation, health education, and disease surveillance are crucial. However, delivery mechanisms are often compromised by loss of health staff, damage to infrastructure, insecurity, and poor co-ordination. Although progress has been made in the control of specific communicable diseases in camp settings, complex emergencies affecting large geographical areas or entire countries pose a greater challenge. Available interventions need to be implemented more systematically in complex emergencies with higher levels of coordination between governments, UN agencies, and non-governmental organisations. In addition, further research is needed to adapt and simplify interventions, and to explore novel diagnostics, vaccines, and therapies.

Ecology of zoonoses: natural and unnatural histories

Summary More than 60% of human infectious diseases are caused by pathogens shared with wild or domestic animals. Zoonotic disease organisms include those that are endemic in human populations or enzootic in animal populations with frequent cross-species transmission to people. Some of these diseases have only emerged recently. Together, these organisms are responsible for a substantial burden of disease, with endemic and enzootic zoonoses causing about a billion cases of illness in people and millions of deaths every year. Emerging zoonoses are a growing threat to global health and have caused hundreds of billions of US dollars of economic damage in the past 20 years. We aimed to review how zoonotic diseases result from natural pathogen ecology, and how other circumstances, such as animal production, extraction of natural resources, and antimicrobial application change the dynamics of disease exposure to human beings. In view of present anthropogenic trends, a more effective approach to zoonotic disease prevention and control will require a broad view of medicine that emphasises evidence-based decision making and integrates ecological and evolutionary principles of animal, human, and environmental factors. This broad view is essential for the successful development of policies and practices that reduce probability of future zoonotic emergence, targeted surveillance and strategic prevention, and engagement of partners outside the medical community to help improve health outcomes and reduce disease threats.

New Strategies for the Elimination of Polio from India

The feasibility of global polio eradication is being questioned as a result of continued transmission in a few localities that act as sources for outbreaks elsewhere. Perhaps the greatest challenge is in India, where transmission has persisted in Uttar Pradesh and Bihar despite high coverage with multiple doses of vaccine. We estimate key parameters governing the seasonal epidemics in these areas and show that high population density and poor sanitation cause persistence by not only facilitating transmission of poliovirus but also severely compromising the efficacy of the trivalent vaccine. We analyze strategies to counteract this and show that switching to monovalent vaccine may finally interrupt virus transmission.

Zika virus and microcephaly: why is this situation a PHEIC?

Fil: Heymann, David L. London School of Hygiene & Tropical Medicine; Reino Unido. The Royal Institute of International Affairs; Reino Unido

Hot spots in a wired world: WHO surveillance of emerging and re-emerging infectious diseases

The resurgence of the microbial threat, rooted in several recent trends, has increased the vulnerability of all nations to the risk of infectious diseases, whether newly emerging, well-established, or deliberately caused. Infectious disease intelligence, gleaned through sensitive surveillance, is the best defence. The epidemiological and laboratory techniques needed to detect, investigate, and contain a deliberate outbreak are the same as those used for natural outbreaks. In April 2000, WHO formalised an infrastructure (the Global Outbreak Alert and Response Network) for responding to the heightened need for early awareness of outbreaks and preparedness to respond. The Network, which unites 110 existing networks, is supported by several new mechanisms and a computer-driven tool for real time gathering of disease intelligence. The procedure for outbreak alert and response has four phases: systematic detection, outbreak verification, real time alerts, and rapid response. For response, the framework uses different strategies for combating known risks and unexpected events, and for improving both global and national preparedness. New forces at work in an electronically interconnected world are beginning to break down the traditional reluctance of countries to report outbreaks due to fear of the negative impact on trade and tourism. About 65% of the worlds first news about infectious disease events now comes from informal sources, including press reports and the internet.

Will Ebola change the game? Ten essential reforms before the next pandemic. The report of the Harvard-LSHTM Independent Panel on the Global Response to Ebola

Harvard Global Health Institute (Prof A Jha MD, S Moon PhD, L R Woskie MSc, J A Leigh MPH), Harvard T.H. Chan School of Public Health (Prof A K Jha, S Moon, L R Woskie, J A Leigh), and Harvard Kennedy School (S Moon), Harvard University, Boston, MA, USA; University of Edinburgh Medical School, Edinburgh (Prof D Sridhar DPhil); Duke Global Health Institute, Durham, NC, USA (M A Pate MD); Bill, Hillary & Chelsea Clinton Foundation, New York, NY, USA (C Clinton DPhil); Medecins Sans Frontieres, New York , NY, USA (S Delaunay MA); Campaign for Good Governance, Freetown, Sierra Leone (V Edwin MA); Action Contre La Faim International , Monrovia, Liberia (M Fallah PhD); Indiana University Maurer School of Law, Bloomington, IN, USA (Prof D P Fidler JD); Council on Foreign Relations, New York, NY, USA (L Garrett PhD); University of California, San Francisco, CA, USA (Prof E Goosby MD); Georgetown University, Washington, DC, USA (Prof L Gostin JD); Chatham House, London, UK (Prof D L Heymann MD); Simon Fraser University, Burnaby, BC, Canada (Prof K Lee DPhil); Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China (Prof G M Leung MD); Center for Strategic and International Studies, Washington DC, USA (J S Morrison PhD); AIDS Executive summary The west African Ebola epidemic that began in 2013 exposed deep inadequacies in the national and international institutions responsible for protecting the public from the far-reaching human, social, economic, and political consequences of infectious disease outbreaks. The Ebola epidemic raised a crucial question: what reforms are needed to mend the fragile global system for outbreak prevention and response, rebuild confi dence, and prevent future disasters? To address this question, the Harvard Global Health Institute and the London School of Hygiene & Tropical Medicine jointly launched the Independent Panel on the Global Response to Ebola. Panel members from academia, think tanks, and civil society have collectively reviewed the worldwide response to the Ebola outbreak. After diffi cult and lengthy deliberation, we concluded that major reforms are both warranted and feasible. The Panel’s conclusions off er a roadmap of ten interrelated recommendations across four thematic areas:

Protective efficacy of a monovalent oral type 1 poliovirus vaccine: a case-control study

BACKGROUND A high-potency monovalent oral type 1 poliovirus vaccine (mOPV1) was developed in 2005 to tackle persistent poliovirus transmission in the last remaining infected countries. Our aim was to assess the efficacy of this vaccine in India. METHODS We estimated the efficacy of mOPV1 used in supplementary immunisation activities from 2076 matched case-control pairs of confirmed cases of poliomyelitis caused by type 1 wild poliovirus and cases of non-polio acute flaccid paralysis in India. The effect of the introduction of mOPV1 on population immunity was calculated on the basis of estimates of vaccination coverage from data for non-polio acute flaccid paralysis. FINDINGS In areas of persistent poliovirus transmission in Uttar Pradesh, the protective efficacy of mOPV1 was estimated to be 30% (95% CI 19-41) per dose against type 1 paralytic disease, compared with 11% (7-14) for the trivalent oral vaccine. 76-82% of children aged 0-23 months were estimated to be protected by vaccination against type 1 poliovirus at the end of 2006, compared with 59% at the end of 2004, before the introduction of mOPV1. INTERPRETATION Under conditions where the efficacy of live-attenuated oral poliovirus vaccines is compromised by a high prevalence of diarrhoea and other infections, a dose of high-potency mOPV1 is almost three times more effective against type 1 poliomyelitis disease than is trivalent vaccine. Achieving high coverage with this new vaccine in areas of persistent poliovirus transmission should substantially improve the probability of rapidly eliminating transmission of the disease.

Global health security: the wider lessons from the west African Ebola virus disease epidemic

Summary The Ebola virus disease outbreak in West Africa was unprecedented in both its scale and impact. Out of this human calamity has come renewed attention to global health security—its definition, meaning, and the practical implications for programmes and policy. For example, how does a government begin to strengthen its core public health capacities, as demanded by the International Health Regulations? What counts as a global health security concern? In the context of the governance of global health, including WHO reform, it will be important to distil lessons learned from the Ebola outbreak. The Lancet invited a group of respected global health practitioners to reflect on these lessons, to explore the idea of global health security, and to offer suggestions for next steps. Their contributions describe some of the major threats to individual and collective human health, as well as the values and recommendations that should be considered to counteract such threats in the future. Many different perspectives are proposed. Their common goal is a more sustainable and resilient society for human health and wellbeing.

Hajj: infectious disease surveillance and control

Summary Religious festivals attract a large number of pilgrims from worldwide and are a potential risk for the transmission of infectious diseases between pilgrims, and to the indigenous population. The gathering of a large number of pilgrims could compromise the health system of the host country. The threat to global health security posed by infectious diseases with epidemic potential shows the importance of advanced planning of public health surveillance and response at these religious events. Saudi Arabia has extensive experience of providing health care at mass gatherings acquired through decades of managing millions of pilgrims at the Hajj. In this report, we describe the extensive public health planning, surveillance systems used to monitor public health risks, and health services provided and accessed during Hajj 2012 and Hajj 2013 that together attracted more than 5 million pilgrims from 184 countries. We also describe the recent establishment of the Global Center for Mass Gathering Medicine, a Saudi Government partnership with the WHO Collaborating Centre for Mass Gatherings Medicine, Gulf Co-operation Council states, UK universities, and public health institutions globally.