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Table 3 Frequency, severity, duration and viral load associated with URTI according to gargling allocation

From: Vitamin D3and gargling for the prevention of upper respiratory tract infections: a randomized controlled trial

Outcome measure Clinical URTI Laboratory confirmed URTI
Gargling (n = 256) Control (n = 236) Effect measure (95% CI) P value Gargling (n = 254) Control (n = 235) Effect measure (95% CI) P value
Imputed URTI episodes, No. (%) 106 (35.3) 100 (33.3) *RR: 1.1 (0.78-1.44) 0.69     
Complete case URTI episodes, No. (%) 85 (33.2) 65 (27.5) *RR: 1.2 (0.92-1.57) 0.19 33 (13.0) 37 (18.7) *RR:0.82 (0.53-1.26) 0.36
Viral load, mean (SD)      6.24 (1.3) 5.95 (1.5)   0.43
Symptom duration, mean days (SD) 6.2 (1.3) 6.0 (1.6) *HR: 0.85 (0.38-1.89) 0.69 5.9 (1.3) 6.1 (1.4) *HR: 0.43 (0.56-4.0) 0.43
Symptom severity, mean (SD) 225.3 (123.9) 191.8 (105.1)   0.13 210.5 (105.3) 191.8 (98.8)   0.49
  1. RR: relative risk, HR: Hazard ratio.
  2. *The Poisson and Cox regression models were adjusted exclusively for randomization strata: vitamin D allocation, gargling allocation, year of participation and type of housing.
  3. Viral load was measured as log10 viral copies/mL.
  4. Symptom duration and severity was measured only in participants who self-reported illness (ie. not for adjudicated events), n = 106. For clinical URTI, n = 55 and n = 51 in the gargling and control groups respectively. For laboratory confirmed URTI n = 26 and n = 30 in the gargling and control groups respectively.