Table 3

HRs from shared frailty Cox proportional hazards model for household members in masks versus control arms (n=597)*

HR (95% CI)†
HR (95% CI)†
Laboratory-confirmed viral respiratory infections
HR (95% CI)†
Masks arm (index case)0.61 (0.18 to 2.13)0.32 (0.03 to 3.13)0.97 (0.06 to 15.54)
Control arm (index case)RefRefRef
Age (household)1.03 (1.01 to 1.05)
  • *Household members (mask arm 302 and control arm 295).

  • †Multivariate analysis was performed as there were 10 cases of CRI and age was also significant in the univariate analysis. Multivariate analyses were not performed for ILI and laboratory-confirmed viral respiratory infections due to the low number of cases.

  • CRI, clinical respiratory illness; ILI, influenza-like illness.