Modelling the global spread of a MERS: Predicting transmission dynamics and simulating vaccine trials for a pandemic MERS variant

ABSTRACT
Middle East Respiratory Syndrome (MERS) is a viral respiratory infection caused by a betacoronavirus in the same genus as SARS-CoV-1 and SARS-CoV-2. The majority of MERS cases detected to-date were clinically severe and approximately 35% had a fatal outcome. While the basic reproduction number for MERS has consistently been estimated to be subcritical, and MERS outbreaks have to-date been limited in size, there are concerns that the MERS coronavirus, or related merbecoviruses, could mutate to support more sustained human-to-human transmission, as seen with SARS and COVID-19. MERS is therefore one of the priority pathogens of the Coalition for Epidemic Preparedness Innovations (CEPI), a global partnership funding the development of vaccines against epidemic and pandemic threats. Its 100 Days Mission aims to respond to a novel Disease X threat within three months. Achieving this ambitious target will not only require up-front investment into the development of vaccine platforms and backbones, but also consideration of how a candidate vaccine would be evaluated in the early phase of a novel disease outbreak, and which evaluation strategy is most likely to deliver actionable results in a short timeframe. To this end, epidemic modelling and trial simulation are helpful and versatile tools to understand how different study methodologies interact with the dynamic of the outbreak and affect the pace and precision of vaccine effect evaluation. I aim to use the GLEAM model, a global spatially structured stochastic metapopulation model, to explore the most likely global spread of an emerging MERS-X variant. Further, I plan to evaluate the impact of an early mass gathering event like the Hajj pilgrimage, attended by millions of pilgrims from all over the world, on the size and trajectory of the pandemic. The outputs of the model will be used to help guide trial site selection and simulate different vaccine trial designs.