Table 4

Number and proportion of participants reporting primary outcomes, by mask versus no-mask groups (n=597)*

CRI No (rate person-days)RRILI
No (rate person-days)
RRLaboratory-confirmed viral respiratory infections
No (rate person-days)
Mask group3/2694 (1.11/1000)0.23 (0.06 to 0.88)1/2694 (0.37/1000)0.18 (0.02 to 1.71)0/2694 (0/1000)0.11 (0.01 to 4.40)
No-mask group7/1440 (4.86/1000)Ref3/1440 (2.08/1000)Ref2/1440 (0.70/1000)Ref
  • *Household members (mask group 387 and no-mask group 210).

  • †Calculated through Cox PH methods.

  • CRI, clinical respiratory illness; ILI, influenza-like illness; PH, proportional hazards; RR, relative risk.