TNSS was obtained from 4 individual nasal sym. including nasal congestion, rhinorrhoea, nasal itch and sneezing. Participants rated sym. on a 4-point scale. For nasal blockage and congestion the scores were (0= Breathing through nose freely and easily, 1= Slight difficulty breathing through nose, 2= Moderate difficulty breathing through nose and 3= Severe difficulty breathing through nose). For rhinorrhoea, nasal itching and sneezing (0= None: No sym. whatsoever; Absent, 1= Mild: Sym. is present, noticeable but not bothersome, 2= Moderate: Sym. is bothersome, but tolerable and 3= Severe: Sym. which are bothersome, harder to tolerate). The individual sym. scores were combined to produce a TNSS. TNSS were reported as median (credible interval). The baseline values were the latest pre-dose assessments. Change from baseline was measured as the value recorded at 15 min post-NAC minus Baseline value.

TNSS was obtained from 4 individual nasal sym. including nasal congestion, rhinorrhoea, nasal itch and sneezing. Participants rated sym. on a 4-point scale. For nasal blockage and congestion the scores were (0= Breathing through nose freely and easily, 1= Slight difficulty breathing through nose, 2= Moderate difficulty breathing through nose and 3= Severe difficulty breathing through nose). For rhinorrhoea, nasal itching and sneezing (0= None: No sym. whatsoever; Absent, 1= Mild: Sym. is present, noticeable but not bothersome, 2= Moderate: Sym. is bothersome, but tolerable and 3= Severe: Sym. which are bothersome, harder to tolerate). The individual sym scores were combined to produce a TNSS. TNSS were reported as median (credible interval). The baseline values were the latest pre-dose assessments. Change from baseline was measured as the value recorded at a specified time point minus Baseline value. Weighted mean (WM) 0-1h of 15, 30 min and 1 h was reported.

TNSS was obtained from 4 individual nasal sym. including nasal congestion, rhinorrhoea, nasal itch and sneezing. Participants rated sym. on a 4-point scale. For nasal blockage and congestion the scores were (0= Breathing through nose freely and easily, 1= Slight difficulty breathing through nose, 2= Moderate difficulty breathing through nose and 3= Severe difficulty breathing through nose). For rhinorrhoea, nasal itching and sneezing (0= None: No sym. whatsoever; Absent, 1= Mild: Sym. is present, noticeable but not bothersome, 2= Moderate: Sym. is bothersome, but tolerable and 3= Severe: Sym. which are bothersome, harder to tolerate). The individual sym scores were combined to produce a TNSS. TNSS were reported as median (credible interval). The baseline values were the latest pre-dose assessments. Change from baseline was measured as value recorded at a specified time point minus Baseline value. WM 0-6 h of 15, 30 min, 1, 2, 3, 4, 5, 6h was reported.

TNSS was obtained from 4 individual nasal sym.: nasal congestion, rhinorrhoea, nasal itch and sneezing. Par rated sym. on a 4-point scale. For nasal blockage and congestion the scores were (0= Breathing through nose freely and easily, 1= Slight difficulty breathing through nose, 2= Moderate difficulty breathing through nose and 3= Severe difficulty breathing through nose). For rhinorrhoea, nasal itching and sneezing (0= None: No sym. whatsoever; Absent, 1= Mild: Sym. is present, noticeable but not bothersome, 2= Moderate: Sym. is bothersome, but tolerable and 3= Severe: Sym. which are bothersome, harder to tolerate). The individual sym. scores were combined to produce a TNSS. TNSS were reported as median (credible interval). BL values were the latest pre-dose assessments. Change from BL was measured as the value recorded at a specified time point minus BL value. The max change from BL from the set of individual PNIF % reduction measurements made over the 0 to 6 h sampling period.

PNIF data recorded at Baseline pre-challenge and at 15, 30 min and 1h. The percent change from Baseline and at specified time point was derived by the formula (PNIF at Baseline minus PNIF at Post-NAC specified time point) divided by PNIF at Baseline) multiplied by 100. The baseline values were the latest pre-dose assessments. The baseline value were the latest pre-dose assessments. Percent change in PNIF were reported as median (credible interval). WM 0-1 h of 15, 30 min and 1 h was reported. WM were derived by first calculating the AUC using the trapezoidal rule, and then dividing by the time interval. If available, actual times were used in the calculation, otherwise planned relative times were used for the calculation.

PNIF data recorded at Baseline pre-challenge and at 15, 30 min and 1h. The percent change from Baseline and at specified time point was derived by the formula (PNIF at Baseline minus PNIF at Post-NAC specified time point) divided by PNIF at Baseline) multiplied by 100. The baseline values were the latest pre-dose assessments. Percent change in PNIF were reported as median (credible interval). WM 0-1 h of 15, 30 min and 1 h was reported. WM were derived by first calculating the AUC using the trapezoidal rule, and then dividing by the time interval. If available, actual times were used in the calculation, otherwise planned relative times were used for the calculation.

PNIF data recorded at Baseline pre-challenge and at 15, 30 min, 1, 2, 3, 4, 5, 6h. The percent change from Baseline and at specified time point was derived by the formula (PNIF at Baseline minus PNIF at Post-NAC specified time point) divided by PNIF at Baseline) multiplied by 100. The baseline values were the latest pre-dose assessments. Percent change in PNIF were reported as median (credible interval). WM 0-6h of 15, 30 min, 1, 2, 3, 4, 5, 6h was reported. WM were derived by first calculating the AUC using the trapezoidal rule, and then dividing by the time interval. If available, actual times were used in the calculation, otherwise planned relative times were used for the calculation.

PNIF data recorded at Baseline pre-challenge and at 15, 30 min, 1, 2, 3, 4, 5, 6h. The percent change from Baseline and at specified time point was derived by the formula (PNIF at Baseline minus PNIF at Post-NAC specified time point) divided by PNIF at Baseline) multiplied by 100. The baseline values were the latest pre-dose assessments. Percent change in PNIF were reported as median (credible interval). Maximum change from Baseline till 6h was reported.