The WAIFW matrix for two groups is expressed as where is the transmission coefficient from an infected member of group and a susceptible member of group. Usually specific mixing patterns are assumed.[citation needed]
Assortative mixing occurs when those with certain characteristics are more likely to mix with others with whom they share those characteristics. It could be given by[2] or the general WAIFW matrix so long as. Disassortative mixing is instead when.
Homogenous mixing, which is also dubbed random mixing, is given by.[3] Transmission is assumed equally likely regardless of group characteristics when a homogenous mixing WAIFW matrix is used. Whereas for heterogenous mixing, transmission rates depend on group characteristics.
The social contact hypothesis was proposed byJacco Wallinga [nl], Peter Teunis, and Mirjam Kretzschmar in 2006. The hypothesis states that transmission rates are proportional to contact rates, and allows for social contact data to be used in place of WAIFW matrices.[5]
^Keeling, Matt J.; Rohani, Pejman (2011).Modeling Infectious Diseases in Humans and Animals. Princeton University Press. p. 58.ISBN978-1-4008-4103-5.
^abHens, Niel; Shkedy, Ziv; Aerts, Marc; Faes, Christel; Van Damme, Pierre; Beutels, Philippe (2012).Modeling Infectious Disease Parameters Based on Serological and Social Contact Data - A Modern Statistical Perspective. Springer.ISBN978-1-4614-4071-0.
^Goeyvaerts, Nele; Hens, Niel; Ogunjimi, Benson; Aerts, Marc; Shkedy, Ziv; Van Damme, Pierre; Beutels, Philippe (2010), "Estimating infectious disease parameters from data on social contacts and serological status",Journal of the Royal Statistical Society, Series C (Applied Statistics),59 (2),Royal Statistical Society:255–277,arXiv:0907.4000,doi:10.1111/j.1467-9876.2009.00693.x,S2CID15947480
^Vynnyvky, Emilia; White, Richard G. (2010),An Introduction to Infectious Disease Modelling, OUP Oxford,ISBN978-0-19-856-576-5
^Wallinga, Jacco; Teunis, Peter; Kretzschmar, Mirjam (2006), "Using Data on Social Contacts to Estimate Age-specific Transmission Parameters for Respiratory-spread Infectious Agents",American Journal of Epidemiology,164 (10):936–944,doi:10.1093/aje/kwj317,hdl:10029/6739,PMID16968863