Guessing treatment on the first day
| Placebo | Zinc lozenge | |
| Total | 42 | 43 |
| Guessed placebo | 5 | 7 |
| Guessed zinc | 8 | 10 |
| No guess | 29 | 26 |
Two participants of the zinc lozenge group are not included since they were unable to fill the web-based questionnaire. We tested if treatment and guessing were independent on lines 2 and 3 (p=0.9 in the χ2 test).