Table 1:
Model parameters
| Value | Domain | Source(s) | |
|---|---|---|---|
| Model calibration target | |||
| Gonorrhoea prevalence at start (calibration target mean) | 0·03 (ie, 3·0%) | (0,1) | .. |
| Model population, sexual behaviour parameters | |||
| N, population size | 106 | (0,¥) | Assumption |
| n, relative size of sexual activity groups | .. | .. | Tuite et al, 201717 |
| Low | n1=0·3 | (0,1) | .. |
| Intermediate | n2=0·6 | (0,1) | .. |
| High | n3=0·1 | (0,1) | .. |
| θ, rate of partner change per sexual activity group (per year) | .. | .. | Model fitting; Tuite et al, 201717 |
| Low (θ1) | 1*1·22 | (0,¥) | .. |
| Intermediate (θ2) | 5*1·22 | (0,¥) | .. |
| High (θ3) | 20*1·22 | (0,¥) | .. |
| ε, mixing parameter | 0·24 | (0,1) | Model fitting; Tuite et al, 201717 |
| Proportion of cases drug A (ceftriaxone-like) resistant at start | 0·0001 | (0,1) | CDC GISP 2020;12 Tuite et al, 201717 |
| Proportion of cases drug B (new drug) resistant at start | 0 | (0,1) | Assumption |
| ρ, model entry or exit rate (per year) | 1/20 | (0,¥) | Tuite et al, 201717 |
| Gonorrhoea natural history parameters | |||
| σ, proportion of incident infections that are symptomatic | 0·60 | (0,1) | Model fitting; Tuite et al, 201717 |
| b, transmission probability per partnership | 0·46 | (0,1) | Model fitting; Fingerhuth et al, 2016;15 Tuite et al, 2017;17 Tuite et al, 201818 |
| δ, natural recovery rate from infection (per year) | 1/0·462 | (0,¥) | Model fitting; Tuite et al,2017;17 Vegvari et al, 202019 |
| Treatment parameters | |||
| Ts, treatment rate if initial treatment success, symptomatic infection (per year) | 1/0·031 | (0,¥) | Model fitting; Tuite et al, 2017;17 Tuite et al, 201818 |
| Tsr, treatment rate if initial treatment failure (requiring retreatment), symptomatic infection (per year) | Ts/3 | (0,¥) | Model fitting; Tuite et al, 201717 |
| Tm, screening rate, asymptomatic infection (per year) | 0·40 | (0,¥) | Model fitting; Tuite et al, 2017;17 Tuite et al 2018;18 Hui et al, 201320 |
| ξ, probability of receiving drug upon initial treatment | |||
| Assumption | |||
| Drug A (ξA) | Strategy dependent | (0,1) | .. |
| Drug B (ξB) | Strategy dependent | (0,1) | .. |
| ω, probability of emergence of resistance upon treatment | |||
| Drug A (ωA) | 10−8 | (0,1) | Tuite et al, 2017;17 Vegvari et al, 202019 |
| Drug B (ωB) | 10−4 (10−10–10−2) | (0,1) | Assumption (range) |
| Drugs A and B (ωAB) | ωA*ωB | (0,1) | Assumption |
| f, relative fitness of resistant bacteria, compared to susceptible | |||
| A resistant (fA) | 0·98 | (0,1) | Tuite et al, 201717 |
| B resistant (fB) | 0·95 (0·80–1) | (0,1) | Assumption (range) |
| Dual A and B resistance (fAB) | fA*fB | (0,1) | Assumption |
| ks, proportion receiving retreatment if initial treatment failure, symptomatic infection | 0·90 | (0,1) | Tuite et al, 201717 |
Parameters determined through model fitting might also cite previous literature sources, which were used to inform starting values for the maximum likelihood estimation procedure. CDC GISP=US Centers for Disease Control and Prevention Gonococcal Isolate Surveillance Project. ¥=infinity.