Hand sanitiser provision for reducing illness absences in primary school children in New Zealand: Cluster randomised trial

We undertook a cluster randomized trial to assess the effects of hand sanitizer on illness absences in pupils of 68 primary schools in the South Island of New Zealand. All pupils received a hand hygiene education session, and schools were randomized to either the provision of hand sanitizer in all classrooms, or usual practice, for 20 weeks over the winter. Each week, information on absences was collected from each school and the parents of a subgroup of children were telephoned to find out about the reason for absence.

The primary outcome was the incidence rate of absence episodes due to any illness; secondary outcomes included respiratory illness, gastrointestinal illness, absence for any reason, and the length of illness and absence. Estimates of intervention effect for follow-up children were calculated from marginal models using generalized estimating equations, with robust variance estimation, to account for correlation of responses of children within schools.

Post absence phone calls resulted in establishing an absence reason for 3846 absences, of which 2,833 were due to illness. The rate of absence due to any illness was similar in the intervention (1.21 per 100 days) and control groups (1.16 per 100 days), and the confidence interval for the incidence rate ratio (IRR = 1.06; 95%CI 0.94, 1.18) excluded a clinically important difference. Furthermore, there was no evidence that hand sanitizers were effective in reducing rates of respiratory or gastrointestinal illness episodes, or the length of the episodes, to any clinically important degree.