Table 1. Planned outcomes from protocol [19] and outcomes actually measured.

Outcome	Planned	Collected	Definition
Primary outcome
Number of absence episodes due to any illness1	Y	Y	An absence episode that, in the follow-up phone call, was reported to be due to any illness. An absence episode was defined as a series of one or more days of absence from school, with a new episode defined as one in which there were at least three days with no absence since the previous absence episode (including week and weekend days).
Secondary outcomes in follow-up children
Number of absence episodes due to respiratory illness	Y2	Y	An absence episode due to illness that includes at least two of the following caregiver-reported symptoms for 1 d, or one of the following symptoms for 2 d (but not fever alone): runny nose, stuffy or blocked nose or noisy breathing, cough, fever, sore throat or sneezing.
Number of absence episodes due to gastrointestinal illness	Y	Y	An absence episode due to illness that does not meet the criteria for respiratory illness and includes either diarrhoea or vomiting or both for at least 1 d.
Length of illness absence episode	Y	Y	Number of days the child was absent from school during an illness episode.
Length of illness episode	Y2	Y	Number of days the illness episode lasted; calculated as the number of days from the first to last day of the absence episode, plus 1 d if the first day of the absence episode was a Monday and plus 1 d if the last day of the absence episode was a Friday.
Number of household members who became ill within 1 wk of the participating child's illness onset	Y	N
Number of episodes where at least one other adult in the household had the same illness after the child	N	Y	As reported by caregiver in follow-up phone call.
Number of episodes where at least one other child in the household had the same illness after the child	N	Y	As reported by caregiver in follow-up phone call.
Secondary outcomes in all children
Number of absence episodes for any reason	Y	Y	Absence episodes for any reason; identified from the school roll. A new absence is defined in the same way as for the primary outcome.
Length of absence episode for any reason	Y	Y	Number of days the child was absent from school during an absence episode.
Adverse events
Skin reactions1	Y	Y	As reported by caregiver in phone call after the end of the study (asked whether child had any skin problems in the winter school terms, and whether any eczema was better, worse, or the same as usual during the study period). A skin reaction was coded as yes if there were any skin problems or if their eczema was worse.

¹Follow-up children only.

²See Table 2 for detail of change to definition.