Table 1. Results from the Bayesian hierarchical model of meningococcal meningitis (MM) A annual incidence at the health centre catchment area (HCCA) level over the study region, Niger 2004–2010.
| Null Model | Multivariate model | |||
| Parameters | Posterior mean | 95% CI* | Posterior mean | 95% CI* |
| Fixed effects (IRR † ) | ||||
| Early cases (yes vs. no) | 6.801 | (4.004,10.910) | ||
| Neighbouring HCCAs with MM A cases‡ (%) | 2.365 | (2.078,2.695) | ||
| Road (yes vs. no) | 1.743 | (1.173,2.474) | ||
| Early rains (yes vs. no) | 0.353 | (0.239,0.502) | ||
| Mean seasonal humidity‡ (%) | 0.656 | (0.405,0.949) | ||
| Random effects | ||||
| Spatial structured hyperparameter (σu2) | 1.470 | (0.799,2.295) | 0.174 | (0.010,0.488) |
| Spatial unstructured hyperparameter (σv2) | 1.965 | (1.278,2.761) | 2.579 | (1.974,3.294) |
| Temporal hyperparameter (σφ2) | 1.755 | (0.539,5.154) | 0.303 | (0.073,0.978) |
| Overdispersion parameter (κ−1) | 4.009 | (3.485,4.601) | 2.586 | (2.223,2.998) |
Posterior mean parameter estimates and their 95% credible intervals (CIs) for the “null” model (no covariates included) and the multivariate model.
* CI: Bayesian credible interval.
†
IRR: Incidence rate ratio.
‡
Standardized variables.