What Role Did the CDC Play in the Ebola Response?

The 2014-2016 Ebola epidemic was one of the largest of its kind, with a death total of more than 11,300 people in Guinea, Liberia, and Sierra Leone.  The US government played a major role in helping to bring the epidemic under control, according to a special supplement to the Morbidity and Mortality Weekly Report published online.¹

The Centers for Disease Control and Prevention (CDC) response was directed at controlling the epidemic in West Africa while also strengthening preparedness for Ebola in the United States, according to the supplement.

CDC activated its Emergency Operations Center (EOC) for the Ebola response on July 9, 2014. On August 5, 2014, CDC officials elevated the EOC to a level 1 activation, its highest level.

“The world came together in an unprecedented way — nations, organizations, and individuals — to respond to this horrible epidemic,” Inger Damon, MD, PhD, who served as incident manager for the CDC Ebola response during its first 8 months, said in a prepared statement about the supplement.²

By the end of the CDC Ebola response, more than 3700 CDC staff, including all 158 Epidemic Intelligence Service Officers, had participated in response efforts. There were 2292 total deployments to Guinea, Liberia, and Sierra Leone and 3544 total deployments (domestic and international) to support the response.

Even after the deactivation of the CDC 2014-2016 Ebola response in March of 2016, CDC officials continue their work to better understand and combat the Ebola virus and to assist health officials in the aftermath of the Ebola epidemic.

Experience with responding to approximately 20 Ebola outbreaks since 1976 provided CDC responders with an understanding of the disease and how to stop Ebola spread. However, unlike those shorter, self-limited outbreaks, the 2014-2016 Ebola epidemic in West Africa presented new challenges and necessitated many steps in both West Africa and the United States, according to the supplement.

In West Africa, the CDC:

• Established research teams in Guinea, Liberia, and Sierra Leone that transitioned into permanent CDC country offices  
• Improved case detection and contact tracing; maintained infection control in Ebola treatment units and general healthcare facilities; conducted detailed epidemiologic analyses of Ebola trends and transmission patterns
• Strengthened surveillance and response capacities in surrounding, at-risk countries, and worked with international partners to establish exit and entry risk assessment procedures at borders

CDC, along with the College of Medicine and Allied Health Sciences of the University of Sierra Leone and the Sierra Leone Ministry of Health and Sanitation, also sought to speed development of an Ebola vaccine. In October 2014, they planned the Sierra Leone Trial to Introduce a Vaccine against Ebola (STRIVE) to evaluate a potential candidate — the recombinant vesicular stomatitis virus Ebola vaccine (rVSV-ZEBOV).

Prior to initiation of STRIVE, all invested parties mounted a research platform in Sierra Leone; trained more than 300 national staff; and implemented ways to effectively and comprehensively communicate with the public before and during the trial to increase awareness and knowledge about the vaccine and the trial.³

The phase 2/3 trial included 8673 participants who were randomly assigned to 1 dose at the beginning of the study or 1 dose 18 to 24 weeks after enrollment. Of these participants, 453 were part of the safety substudy and 539 were part of the immunogenicity substudy. Results as of April 28, 2016 indicated that there have been no Ebola cases or serious vaccine-related adverse events.

“Although STRIVE will not be able to measure vaccine efficacy because of the absence of reported Ebola virus transmission in healthcare workers during the study period, STRIVE will provide key data on safety, reactogenicity, and immunogenicity to inform licensure,” according to the supplement. “The impact and accomplishments also extend beyond contributing data needed for vaccine licensure and support any vaccine deployment. These include lessons on acceptance of the vaccine; improved cold chain infrastructure, including various new technologies; capacity for basic laboratory work and data management; communication expertise; and staff experienced with this vaccine.”

In the United States, CDC officials assisted in the response by:

• Reducing the likelihood of Ebola spread through travel, including work with federal and state health officials to establish entry risk assessment procedures
• Establishing entry screening and monitoring of all travelers entering the United States from Ebola-affected areas
• Assisting state health departments in responding to domestic Ebola concerns
• Forming CDC Rapid Ebola Preparedness (REP) response teams that could provide assistance within 24 hours to a healthcare facility managing a patient with Ebola
• Identifying and distributing to state and local public health laboratories a laboratory assay that could reliably detect infection with the Ebola virus strain circulating in West Africa, and working with the US Food and Drug Administration, the US Department of Defense, and the Association of Public Health Laboratories to rapidly introduce the assay in public health laboratories across the United States

“This outbreak highlighted how much more we have to learn about Ebola, and it demonstrated that all countries are connected. An outbreak in 1 country is not just a national emergency, but a global one. This supplement’s detailed review of the 2014-2016 Ebola epidemic and CDC’s response, with many partners, shows the importance of preparedness. It is vital that countries are ready to quickly detect and respond to infectious disease outbreaks, and the international community is committed to increasing that readiness through the Global Health Security Agenda,” CDC Director Tom Frieden, MD, MPH, said in the statement. “Through our newly established country offices in Guinea, Liberia, and Sierra Leone, CDC will continue to help West Africa prevent an outbreak of this magnitude from happening again.”

References

1. CDC. CDC’s Response to the 2014–2016 Ebola Epidemic — West Africa and United States. MMWR. 2016;65(3):1-112.

2. CDC Media Relations. CDC Releases Detailed History of the 2014-2016 Ebola Response in MMWR [press release]. Atlanta, GA; CDC: July 7, 2016.

3. CDC. Implementing an Ebola Vaccine Study — Sierra Leone.. Supplements. 2016; 65(3):98–106.