Heterogeneous mixing

Homogeneous mixing assumes that individuals interact without systematic differences. Heterogeneous mixing allows contact and transmission opportunities to vary between individuals or groups.

Sources of heterogeneity

Mixing can vary by age, household, workplace, school, geography, behaviour, occupation or network position.

Why it changes epidemic dynamics

Individuals with many contacts may both acquire and transmit infection more frequently. Concentrating transmission in highly connected groups can alter invasion thresholds, epidemic size and intervention effectiveness.

Mathematical representation

Heterogeneity may be represented using multiple compartments, contact matrices, spatial structure or explicit contact networks.