| to mass-produce | 6 | purpose |
| very | 3 | degree |
| vaccine → be → difficult | 11 |
| vaccine → be difficult to → administer | 3 |
| vaccine → be → tricky | 3 |
| vaccine → be → challenge | 3 |
| negative | neutral | positive |
| 0.565 | 0.347 | 0.088 |
| Raw frequency | 20 |
| Normalized frequency | 0.258 |
| Modifier score | 0.800 |
| Perplexity | 279.129 |