Modelling Vaccination Strategies for the Control of Marburg Virus Disease Outbreaks

Abstract Marburg virus disease is an acute haemorrhagic fever caused by Marburg virus. Marburg virus is zoonotic, maintained in nature in Egyptian fruit bats, with occasional spillover infections into humans and nonhuman primates. Although rare, sporadic cases and outbreaks occur in Africa, usually associated with exposure to bats in mines or caves, and sometimes with secondary human-to-human transmission. Outbreaks outside of Africa have also occurred due to importation of infected monkeys. Although all previous Marburg virus disease outbreaks have been brought under control without vaccination, there is nevertheless the potential for large outbreaks when implementation of public health measures is not possible or breaks down. Vaccines could thus be an important additional tool and development of several candidate vaccines is under way. We developed a branching process model of Marburg virus transmission and investigated the potential effects of several prophylactic and reactive vaccination strategies in settings driven primarily by multiple spillover events as well as human-to-human transmission. Our results show a low basic reproduction number which varied across outbreaks, from 0.5 [95% CI: 0.05 – 1.8] to 1.2 [95% CI: 1.0 – 1.9] but a high case fatality ratio. Of six vaccination strategies explored, a combination of ring and targeted vaccination of high-risk groups was generally most effective, with a probability of controlling potential outbreaks of 0.88 (95% CI: 0.85 - 0.91) compared with 0.65 (0.60 - 0.69) for no vaccination, especially if the outbreak is driven by zoonotic spillovers and the vaccination campaign initiated as soon as possible after onset of the first case. Author Summary Marburg virus disease is a rare but acute haemorrhagic fever caused by Marburg virus. We developed a branching process model of Marburg virus transmission and used this model to investigate potential prophylactic and reactive vaccination strategies in settings driven primarily by multiple spillover events as well as human-to-human transmission. We calculate a low basic reproduction number which varied across outbreaks, from 0.5 [95% CI: 0.05 – 1.8] to 1.2 [95% CI: 1.0 – 1.9]. Of the six vaccination strategies explored, a combination of ring and targeted vaccination of high-risk groups was generally most effective, with a probability of controlling potential outbreaks of 0.88 (95% CI: 0.85 - 0.91) compared with 0.65 (0.60 - 0.69) for no vaccination, especially if the outbreak is driven by zoonotic spillovers and the vaccination campaign initiated as soon as possible after onset of the first case.