On July 2, the World Health Organization announced the end of the latest Ebola outbreak, which took place in the Democratic Republic of Congo’s northern province of Bas-Uele. All told, four people died during the two-month outbreak, while four people survived infection with the virus. “With the end of this epidemic, DRC has once again proved to the world that we can control the very deadly Ebola virus if we respond early in a coordinated and efficient way,” said the WHO’s director-general, Dr. Tedros Adhanom Ghebreyesus. While Congo has extensive experience with Ebola, and the latest outbreak took place in a remote region where it was relatively easy to contain, public health officials continue to prepare for the possibility of a more difficult outbreak like the one that began in West Africa in 2014. In an email interview, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, provides an update on that effort.
WPR: Did the West Africa Ebola epidemic produce sustainable gains in the world’s ability to respond to future outbreaks—for example, the recent outbreak in northern Democratic Republic of Congo?
Dr. Anthony Fauci: The Ebola outbreak in West Africa underscored the necessity of a sound public health infrastructure, including strong disease surveillance capabilities, when a highly lethal virus begins spreading in a community. The health care systems in Guinea, Liberia and Sierra Leone were quickly overwhelmed, allowing the epidemic to spiral out of control. Health care workers lacked the essential supplies and facilities to protect themselves and properly isolate patients. Contact tracing became increasingly difficult, and traditional burial practices facilitated further spread of the virus. Unlike West Africa, the Democratic Republic of the Congo has considerable experience responding to Ebola outbreaks using proven public health measures. These outbreak control practices, implemented with significant international assistance, ultimately halted the spread of Ebola in West Africa and will remain critically important in controlling future outbreaks.
However, a vaccine against Ebola would be an extremely helpful addition to the public health “toolkit” for the disease. Multiple groups made considerable progress in the clinical development of vaccine candidates during the outbreak in West Africa. In February 2015, NIAID partnered with the Liberian Ministry of Health and Liberian investigators to initiate a vaccine trial and natural history studies. Together we made a commitment to invest in sustainable health infrastructure to get these trials off the ground. Today, Liberia is better prepared to respond to future outbreaks of Ebola as well as other endemic diseases such as malaria and HIV. This effort also demonstrated the feasibility of conducting scientifically rigorous clinical trials in an outbreak setting, even in a resource-limited country.
Ultimately, the Ebola outbreak in West Africa reminded us of the need for a joint commitment to effective epidemic control, as outlined in the Global Health Security Agenda (GHSA). Launched in February 2014, GHSA is a partnership among more than 50 countries and organizations that aims to strengthen global capacity to prevent, detect and limit the spread of infectious disease outbreaks to reduce human suffering and reduce economic impact.
WPR: What is the current status of efforts to develop an Ebola vaccine, and has sufficient energy been spent on this effort since the end of the West Africa epidemic?
Fauci: The international research community is working rapidly to gain as much information as possible on various candidate Ebola vaccines. During the tragic Ebola outbreak of 2014-2016, multiple groups attempted to evaluate the safety and efficacy of vaccines, hoping to leverage effective countermeasures alongside traditional public health measures and control the spread of the virus. The epidemic had begun to wane as the trials began, and so it was not possible to prove conclusively that the vaccine candidates worked. A ring vaccination trial in Guinea, led by the World Health Organization, did show evidence of efficacy for one candidate: Merck’s VSV-ZEBOV. It is likely that the information gained in that trial will play a key role in any future licensure application.
Although the Guinea ring trial yielded important new knowledge, we need additional data for all Ebola vaccine candidates. In particular, we require solid data that will help us determine how quickly protection begins following inoculation and how long it lasts. Large Phase 2 trials—including the Partnership for Research on Ebola VACcination (PREVAC) trial, a collaboration involving NIAID, the French Institute of Health and Medical Research (Inserm), the London School of Hygiene and Tropical Medicine, and health authorities in Guinea and Liberia—are now gathering some of these needed data. PREVAC launched in April 2017 and will identify vaccination regimens that hold promise to protect people from Ebola virus disease, which may enable health authorities to prevent or quickly control any future outbreak.
Should an outbreak occur before we have a licensed Ebola vaccine, regulatory and public health authorities can work together to consider distribution of a vaccine under certain criteria that require close safety monitoring and informed consent of vaccine recipients.