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When should lockdown be implemented? Devising cost-effective strategies for managing epidemics amid vaccine uncertainty
Fig 5
Epidemiological model structure.
Schematic illustrating the structure of the model that governs the disease dynamics. Susceptible individuals (Sa) can acquire infection from any of the four infectious classes (asymptomatic (
), symptomatic without requiring hospital treatment (
), symptomatic and eventually requiring hospital treatment (
) and hospitalised with severe disease (
)), highlighted by the grey box. Immediately following infection, individuals temporarily occupy an exposed class (Ea,m) where they spend the latent period, before progressing to the infectious classes according to age-dependent severity parameters da and ha. At the end of the infectious period, individuals who recover remain in the Ra,m class until they undergo natural waning immunity and return to the susceptible class. Disease-induced mortality occurs in hospital settings at age-dependent probability μa, and deceased individuals are removed from the model. Where relevant, subscripts distinguish between demographic cohorts a ∈ G = {0 − 19, 20 − 64, 65+} and Erlang-stage classification m ∈ {1, 2, 3}.
doi: https://doi.org/10.1371/journal.pcbi.1012010.g005