Osong Public Health and Research Perspectives

Brief Report

Ebola Hemorrhagic Fever and the Current State of Vaccine Development: Joo Eun Hong, Kee-Jong Hong, Woo Young Choi, Won-Ja Lee, Yeon Hwa Choi, Chung-Hyeon Jeong, Kwang-il Cho; Osong Public Health Res Perspect. 2014;5(6):378-382. Published online December 31, 2014; DOI: https://doi.org/10.1016/j.phrp.2014.09.006

Abstract PDF: Current Ebola virus outbreak in West Africa already reached the total number of 1,323 including 729 deaths by July 31st. the fatality is around 55% in the southeastern area of Guinea, Sierra Leone, Liberia, and Nigeria. The number of patients with Ebola Hemorrhagic Fever (EHF) was continuously increasing even though the any effective therapeutics or vaccines has not been developed yet. The Ebola virus in Guinea showed 98% homology with Zaire Ebola Virus.Study of the pathogenesis of Ebola virus infection and assess of the various candidates of vaccine have been tried for a long time, especially in United States and some European countries. Even though the attenuated live vaccine and DNA vaccine containing Ebola viral genes were tested and showed efficacy in chimpanzees, those candidates still need clinical tests requiring much longer time than the preclinical development to be approved for the practical treatment.It can be expected to eradicate Ebola virus by a safe and efficient vaccine development similar to the case of smallpox virus which was extinguished from the world by the variola vaccine.

Invited Original Article

Incubation Period of Ebola Hemorrhagic Virus Subtype Zaire: Martin Eichner, Scott F. Dowell, Nina Firese; Osong Public Health Res Perspect. 2011;2(1):3-7. Published online June 30, 2011; DOI: https://doi.org/10.1016/j.phrp.2011.04.001

Abstract PDF: Objectives
Ebola hemorrhagic fever has killed over 1300 people, mostly in equatorial Africa. There is still uncertainty about the natural reservoir of the virus and about some of the factors involved in disease transmission. Until now, a maximum incubation period of 21 days has been assumed.
Methods
We analyzed data collected during the Ebola outbreak (subtype Zaire) in Kikwit, Democratic Republic of the Congo, in 1995 using maximum likelihood inference and assuming a log-normally distributed incubation period.
Results
The mean incubation period was estimated to be 12.7 days (standard deviation 4.31 days), indicating that about 4.1% of patients may have incubation periods longer than 21 days.
Conclusion
If the risk of new cases is to be reduced to 1% then 25 days should be used when investigating the source of an outbreak, when determining the duration of surveillance for contacts, and when declaring the end of an outbreak.

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