[p1] Applications in various physical and biological systems


Rubella epidemic modelling and distribution of vaccines in Japan

M. M. Saito (The Institute of Mathematics), R. Kinoshita (Hokkaido University), and H. Nishiura (Hokkaido University)


In Japan, the proportion of rubella susceptible person's is currently near the threshold above which a major epidemic may occur. During 2012/13 the number of rubella cases in Japan was relatively large in recent years. The maximum number of weekly reported cases was 168 in Tokyo Prefecture and 268 in Osaka Prefecture while 1-2 or no cases are reported per week in usual years in each prefecture. This epidemic is almost limited to the metropolitan area while below ten cases per week were reported in 30 prefectures. Such a geographical contrast in reported cases reflects that the susceptibility is very close to the threshold of major outbreak. It is necessary to take into account a spillover of the disease via the person's movement and stochastic nature of transmission in order to reproduce such an infection trend. In the present study, it is shown that the 2012/13 epidemic is reproduced better by a stochastic meta-population model than a standard SIR model, under an appropriate model parameter.