A quantitative framework to define the end of an outbreak: application to Ebola Virus Disease

Bimandra A Djaafara; Natsuko Imai; Esther Hamblion; Benido Impouma; Christl A Donnelly; Anne Cori

Various definitions or criteria of an EO have been used in different outbreaks depending on the type of disease and the institutions providing technical guidance or in charge of controlling the outbreak. We retrieved examples of EO criteria from various pathogens and institutions from the literature ( Table 1) . Most of these criteria are obtained from the World Health Organization (WHO) guidelines or decided by a government's Ministry of Health or public health authorities. The most commonly used EO criterion is a period of twice the longest incubation period without observing any new cases since the last possible transmission event (4) (5) (6) (7) (8) (9) (10) (11) (12) . In an Ebola Virus Disease (EVD) outbreak context, the EO of EVD is declared after 42 days (twice the longest incubation period) has passed since the outcome of the last case. There are several possible scenarios of the outcome of the last case (8) . If the last case is a laboratory-confirmed case, the outcome can be the second PCR negative test of blood samples or a safe burial if the person died. Additionally, if the last case is a contact of a confirmed case, the outcome is a safe burial after the person's death.