Studies from University of Tokyo Further Understanding of Mathematics (An Age-structured Epidemic Model With Boosting and Waning of Immune Status)

摘要

2021 SEP 27 (NewsRx) - By a News Reporter-Staff News Editor at Disease Prevention Daily - New research on Mathematics is the subject of a report. According to news reporting from Tokyo, Japan, by NewsRx journalists, research stated, "In this paper, we developed an age-structured epidemic model that takes into account boosting and waning of immune status of host individuals. For many infectious diseases, the immunity of recovered individuals may be waning as time evolves, so reinfection could occur, but also their immune status could be boosted if they have contact with infective agent." Funders for this research include Japan Society for the Promotion of Science, Japan Society for the Promotion of Science. The news correspondents obtained a quote from the research from the University of Tokyo, "According to the idea of the Aron's malaria model, we incorporate a boosting mechanism expressed by reset of recovery-age (immunity clock) into the SIRS epidemic model. We established the mathematical well-posedness of our formulation and showed that the initial invasion condition and the endemicity can be characterized by the basic reproduction number R-0. Our focus is to investigate the condition to determine the direction of bifurcation of endemic steady states bifurcated from the disease-free steady state, because it is a crucial point for disease prevention strategy whether there exist subcritical endemic steady states. Based on a recent result by Martcheva and Inaba [1], we have determined the direction of bifurcation that endemic steady states bifurcate from the disease-free steady state when the basic reproduction number passes through the unity."