Niffenegger 1997.
| Methods | Prospective 2‐centre cohort study assessing the effects of a handwashing programme in Indiana, USA. Two centres were enrolled for the August to December 1994 (21 weeks) study: a test and a control centre | |
| Participants | Eight teachers and 26 children (aged 3 to 5) in the test group and 12 children and 8 teachers in the control group. According to the authors, age, experience gender and socioeconomic variables were equally distributed between the 2 groups, but data are not shown. No attrition is mentioned | |
| Interventions | Three weekly cycles of teachings, handwashing routine encouragement for children, parents and staff and correct sneezing and coughing procedure. Follow up was weekly filling in of a teacher report. It is unclear from the text what happened in the control site, or indeed if they were fully aware of the project | |
| Outcomes | Laboratory: N/A Effectiveness: colds and ARIs no better defined Safety: N/A | |
| Notes | Risk of bias: high (wide range of incidence of infections)
Notes: the authors conclude that during the first 11 weeks of the study the test centre had double the incidence of colds compared to the control centre this is explained by the author as caused by the influx of new children bringing in new viruses in the test centre. In the second period the reverse was true, explained as the stabilising of the population and the taking effect of the programme. The list of potential confounders and biases is countless. For example there is only a very cursory description of participants in both arms and the role of teachers especially in the control centre is not explained The test group had significantly fewer colds than the control group (P < 0.05) |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | N/A |
| Allocation concealment (selection bias) | Unclear risk | N/A |
| Blinding (performance bias and detection bias) All outcomes | Unclear risk | N/A |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | N/A |
| Selective reporting (reporting bias) | Unclear risk | N/A |