In infectious disease modelling, a who acquires infection from whom (WAIFW) matrix is a matrix that describes the rate of transmission of infection between different groups in a population, such as people of different ages. Used with an SIR model, the entries of the WAIFW matrix can be used to calculate the basic reproduction number using the next generation operator approach.

Examples

. Usually specific mixing patterns are assumed.

Assortative mixing

.

Homogenous mixing

. 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.

Asymmetric mixing

. Examples of asymmetric WAIFW matrices are

Social contact hypothesis

The social contact hypothesis was proposed by and allows for social contact data to be used in place of WAIFW matrices.

See also

• Mathematical modelling of infectious disease

• Next-generation matrix

References