Serotype diversity in invasive pneumococcal disease (IPD) and carriage before and after vaccine introduction calculated using the Simpson index of diversity
| Simpson index (95% CI) | p-value | ||
| Before | After | ||
| IPD | 0.928 (0.921–0.935) | 0.946 (0.942–0.950) | <0.001 |
| Carriage | 0.885 (0.866–0.904) | 0.930 (0.922–0.938) | <0.001 |