4.2. URTIs Episodes
URTIs, infection, infections, upper respiratory tract symptoms
RESPIRATORY TRACT INFECTION, INFECTION, EVENTS, INFECTIONS
The traditional understanding of URTI is that it appears as a streak of consecutive days with upper respiratory tract symptoms, usually lasting for 3 to 7 or more days, which can be defined as infectious episode [Analyzing our data, we initially attempted to process the results in the way that would allow us to present the statistics on the number of episodes. However, despite collecting very precise daily reports with the level of severity stated for each upper respiratory symptoms set appearance, we were not able to clearly define the URTIs episodes, at least among substantial proportion of our participants. These streaks of symptomatic days were either too long for a typical period of non-chronic respiratory tract infection, were separated by symptomless periods that were too short (less than 3 days), or their severity score was very mild.It seems that reporting URTIs symptoms on daily basis may have become too sensitive a parameter in regard to judging whether the self-registered symptoms were actual signs of the infection or they were just casually appearing, meaningless events (occasional sneezing, for instance). This is why we decided to assess the actual infectious days frequency based on weekly, not daily reports. Reporting weekly gives us a chance to fully assess the meaning of the symptoms and decide whether the particular day was infectious one or not.A high degree of diversity of individual URTIs episodes appearance and their potentially unexpected course can occur for several reasons. One could be having a large variety and still changing the spectrum of infectious agents causing these infections [Consequently, categorizing the symptomatic days into episodes in our opinion is extremely subjective and can produce high bias level in both reporting and analyzing data. Thus, for reliability of the statistics on URTIs, the trial results should preferably be presented as the number of symptomatic days and the severity scores, as we did in this report.