Table 1 Model parameters, the specified prior distribution or functional form, and evidence informing the parameter

c _a,2007,S|Pop

Proportion of population that seroconverted in 2007

Vague prior on logit probability, assuming nothing is known about this parameter

Direct evidence from observed cases with IgG-Ptx titre above sero-diagnostic threshold, PIENTER 2 study

Normal(0,1000)

c _a,t,S|Pop

Proportion of population that seroconverted each year

Random-walk prior assumed, in which seroconversion probability in current year is correlated with that in previous year

All model assumptions and data

Normal(c _a,t-1,S|Pop ,τ _a )

c _a,t,I|Pop

Proportion of population infected in each year

Adjustment for estimated proportion vaccination-related seroconversions

Based on modelling of longitudinal IgG-Ptx dataset

c _a,t,S|Pop  × (1– propVaccRel _a )

c _a,SI|I

Proportion of infected population who are symptomatic

Informative priors, reflecting proportion of seroconversions with reported symptoms, PIENTER 2 study

Direct evidence from number of seropositive household members of infected infants with reported symptoms, BINKI study

Separate Beta distributions for each age-group

d _a,SI

Proportion of true SI cases that are notified

Vague prior, assuming nothing is known about this parameter

All model assumptions and data

Beta(1,1)

N _a,Pop

National population size

N/A

Population size estimates from Statistics Netherlands

N/A

N _a,t,I

Size of infected population in each year

Functional relationship between the incidence and the national population size according to probability of seroconversion, PIENTER 2

All model assumptions and data

N _a,t,Pop  × c _a,t,I|Pop

N _a,t,SI

Size of symptomatically infected population in each year

Functional relationship between the incidence of symptomatic infection and the number of incident infections according to symptomatic probability

Direct evidence from observed number of notified cases (binomial likelihood for ‘true’ number of SI cases with detection probability d _a,SI )

N _a,t,I  × c _a,SI|I

SIAR _a,t

Symptomatic infection attack rate

Symptomatic infection attack rate is defined as the product of component conditional probabilities

All model assumptions and data

c _a,SI|I  × c _a,t,I|Pop