Table 1. Model notation.

Symbol	Meaning
C(i)	Age-dependent susceptibility scaling factor of individual i
T(i)	Age-dependent transmissibility scaling factor of individual i
N H(i)	Number of individuals in an individual i’s household
T H	Baseline transmission rate across household contact
ρ H(i,j)	Household transmission rate from individual j to individual i
T B	Baseline transmission rate across bubble contact, T B = CT H where c ∈ [0 1]
ρ B(i,j)	Bubble transmission rate from individual j to individual i
ε	Baseline mean-field transmission rate
ε(i)	Mean-field transmission rate to an individual i
I g(i)	Infection status of an individual i at generation g. I g(i) = 0 if i is susceptible at generation g. I g(i) = 1 if i has been infected by generation g (so includes recovered individuals)
S g (i)	1 - I g(i), i.e. the susceptibility status of an individual i at generation g.
N	Size of population.