2.2. Final Selection for Analysis
URTIs
The unannounced drop-out of participants without stating any reason for it occurred throughout the trial period and was preceded in most cases by erratic or delayed responses to daily on-line surveys. Therefore, we decided to perform the eligibility assessment based on participation in daily surveys. In addition, upon collecting all the data, it appeared that some participants reported extremely high overall symptom severity scores of URTIs. Consequently, we assessed the validity for final analysis based on individual participants’ daily reporting performance and URTIs scores staying within acceptable limits.In this final selection process, we decided to set a minimal limit of 85 responses to a total of 107 published daily surveys (79.4%) to prove the eligibility for final analysis. Another parameter we used was a total URTIs severity score (for definition, see below in the surveys section) of 59, which we decided to be the highest acceptable. The score of 60 indicated that participant reported at least mild symptoms of URTIs for 56% of the trial duration (60 days out of 107), or more severe symptoms for a relatively shorter amount of time. In our judgement, such a high URTI score value reflected either reckless reporting on the health status by the particular participant or the fact that such individual’s health status did not fit into description of a young, generally healthy individual.Based on responding to at least 85 surveys, we have qualified 179 participants, of whom we additionally excluded 21 subjects due to their URTI score being higher than 59. The final number of subjects qualified for analysis was 158.