Grouping theory of epidemiology

Background (traditional theory)there are general and principle models and calculation formulas for epidemics, mainly the basic reproduction number R0 of a certain epidemic disease such as COVID-19, the newly confirmed number Cn=Rn-1Cn-1, The threshold of herd immunity is (R0-1)/R0. Innovation theoryBased on the fact that there are groups of different tends (that is, different R0 or Rk), a grouping model of epidemiology is proposed, and a complete and detailed calculation formula is given. The basic relationship is that the overall infection numbers of is equal to the sum of the infection number of groups, namely: Rt={sum}(fkRk), where fk is the population proportion of each group, and Rk is the basic reproduction number of each groups. Its important application is the grouping strategy in which prevention and control measures are inclined to high-risk groups. The basic relationship is that the basic reproduction number of each group is equal to the product of the control coefficient of its measures and the original basic reproduction number, namely: Rk={zeta}kR0k. Compared with the traditional strategy of equal treatment, the grouping strategy has the characteristics of high efficiency, low consumption, and low threshold of herd immunity.