The Respiratory Protection Effectiveness Clinical Trial (ResPECT): a cluster-randomized comparison of respirator and medical mask effectiveness against respiratory infections in healthcare personnel

Table 4 Sample size and power calculations for primary and secondary outcome

	Laboratory confirmed influenza	Laboratory confirmed respiratory illness
Annual attack rate, Medical Mask group	0.12	0.25
Cumulative 4-year attack rate, Medical Mask group	0.39	0.68
Detectable relative risk	0.75	0.75
Median cluster size	16	16
ICC	0.1	0.1
Total person-seasons of observation	10,024	5104

ISSN: 1471-2334