30 Oct Ebola: Infectiousness Greatly Increases With Disease Progression
Medical Research: What is the background for this study?
Dr. Yamin: With limited resources, West Africa is currently overwhelmed by the most devastating Ebola epidemic known to date. In our research, we seek to address two questions:
- 1) who is mostly responsible for transmission? and
2) what intervention programs should be applied to contain the current Ebola outbreak?
Medical Research: What are the main findings?
Dr. Yamin: Each infected person is transmitting the disease, on average, to 1.73 other people. However, people who will eventually die from the disease are spreading it even further, resulting in 2.36 people becoming infected. We also found that infectiousness greatly increases with disease progression, and thus isolating 75% of infected individuals in critical condition within four days of symptom onset has a high chance of eliminating the spread of the disease.
Medical Research: What should clinicians and patients take away from your report?
Dr. Yamin: Early case-isolation is paramount to reducing household and community transmission. In the absence of resources, targeted patient isolation may stem Ebola outbreak.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Yamin: The amount of viral load in non-survivors (and consequently their transmissibility) is substantially higher than the viral load of survivors even after two days from the onset of symptoms. However, the non-survivors can be identified only at a more severe stage of the infection by specific clinical symptoms. Future studies are needed to design a clinical algorithm to identify potential survivors from those individuals who are not likely to survive in order to better inform clinical practice.
Effect of Ebola Progression on Transmission and Control in Liberia
Dan Yamin, PhD; Shai Gertler; Martial L. Ndeffo-Mbah, PhD; Laura A. Skrip, MPH; Mosoka Fallah, PhD; Tolbert G. Nyenswah, MPH; Frederick L. Altice, MD, MA; and Alison P. Galvani, PhD
Ann Intern Med. Published online 28 October 2014 doi:10.7326/M14-2255