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arXiv · 1809.02956

Epidemiological impact of waning immunization on a vaccinated population

Ewa Grela·Michael Stich·Amit K Chattopadhyay
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Abstract

This is an epidemiological SIRV model based study that is designed to analyze the impact of vaccination in containing infection spread, in a 4-tiered population compartment comprised of susceptible, infected, recovered and vaccinated agents. While many models assume a lifelong protection through vaccination, we focus on the impact of waning immunization due to conversion of vaccinated and recovered agents back to susceptible ones. Two asymptotic states exist, the "disease-free equilibrium" and the "endemic equilibrium"; we express the transitions between these states as function of the vaccination and conversion rates using the basic reproduction number as a descriptor. We find that the vaccination of newborns and adults have different consequences in controlling epidemics. We also find that a decaying disease protection within the recovered sub-population is not sufficient to trigger an epidemic at the linear level. Our simulations focus on parameter sets that could model a disease with waning immunization like pertussis. For a diffusively coupled population, a transition to the endemic state can be initiated via the propagation of a traveling infection wave, described successfully within a Fisher-Kolmogorov framework.

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Ewa Grela, Michael Stich, Amit K Chattopadhyay. 2018-09-09. Epidemiological impact of waning immunization on a vaccinated population. https://doi.org/10.1140/epjb%2Fe2018-90136-3

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