Sierra Leone

THE LANCET byMichel Van Herp, Hilde Declerck and Tom Decroo June 13, 2015

.. the efficacy of candidate Ebola vaccines for primary prevention has not been proven.² Furthermore, in communities in which Ebola transmission might be ongoing, an important question is: how will such a vaccination be perceived if a vaccinated person develops Ebola? Such a scenario is possible in people who contract Ebola virus before vaccination. If a person is infected with Ebola virus before vaccination, the vaccine might have a post-exposure prophylactic effect. However, how effective this prophylaxis might be is unknown.² Moreover, if someone is infected more than 48 h before vaccination, the post-exposure prophylactic effect is likely to be insufficient, leading to possible development of Ebola after vaccination. This scenario is likely to result in serious issues relating to community trust and acceptance of an Ebola vaccine.³ How to exclude Ebola among people presenting with post-vaccination fever is also an issue.²