An AE is defined as any untoward medical occurrence in a participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. An SAE is defined as any untoward medical occurrence that, at any dose, results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity, or is a congenital anomaly/birth defect, may jeopardize the participant or may require medical or surgical intervention to prevent one of the other outcomes listed in this definition, associated with liver injury and impaired liver function defined as alanine aminotransferase \>=3 x upper limit of normal (ULN), and total bilirubin \>=2 x ULN or international normalised ratio \>1.5. The grading of AEs and SAE's for 3/4 (3= severe, 4= potentially life threatening ) and its classification as potentially drug-related was done based on the investigator's judgment.

The reference ranges for clinical chemistry parameters were ALT 5 to 45 international units per litre \[IU/L\]), ALP 100 to 325 IU/L, creatine kinase 60 to 270 IU/L and AST 10 to 40 IU/L. The baseline assessments were referred to assessments at Day 1. Assessments were done at Day 1, 3 and 5.

The reference ranges for clinical chemistry parameters were creatinine 41.548 - 69.836 micromole per litre (µmol/L), direct bilirubin 0 to 5.13 µmol/L and total bilirubin 3.42 to 20.52 µmol/L. The baseline assessments were referred to assessments at Day 1. Assessments were done at Day 1, 3 and 5.

The reference ranges for clinical chemistry parameters were calcium 2.0958 to 2.5948 millimole per litre (mmol/L), carbon dioxide content/ bicarbonate 19.2 to 27.1 mmol/L, chloride 98 to 108 mmol/L, magnesium 0.7809 to 1.0275 mmol/L, potassium 3.5 to 5 mmol/L, sodium 137 to 147 mmol/L and urea/BUN 2.856 to 8.211 mmol/L. The baseline assessments were referred to assessments at Day 1. Assessments were done at Day 1, 3 and 5.

The reference ranges for clinical chemistry parameters were albumin 38 to 53 grams per liter (g/L) and total protein 67 to 83 g/L. The baseline assessments were referred to assessments at Day 1. Assessments were done at Day 1, 3 and 5.

The reference ranges for hematology parameters were basophils 0 to 2 percentage (%), eosinophils 0 to 8%, lymphocytes 18 to 49%, monocytes 2 to 10%, total neutrophils 40 to 75%, platelet count 140 to 340 giga cells per liter (GI/L), WBC count 3.3 to 9 GI/L, hemoglobin 135 to 175 g/L and haematocrit 0.397 to 0.524 ratio. The baseline assessments were referred to assessments at Day 1. Assessments were done at Day 1, 3, and 5.

Albumin and total protein were measured at Baseline , Day 3 and Day 5 during the treatment period. The baseline assessments were referred to assessments at Day 1. Change from Baseline was calculated as the value at the indicated time point minus the Baseline value.

ALT, ALP, creatine kinase and AST were measured at Baseline, Day 3 and Day 5 during the treatment period. The baseline assessments were referred to assessments at Day 1. Change from Baseline was calculated as the value at the indicated time point minus the Baseline value.

Creatinine, direct bilirubin and total bilirubin were measured at Baseline, Day 3 and Day 5 during the treatment period. The baseline assessments were referred to assessments at Day 1. Change from Baseline was calculated as the value at the indicated time point minus the Baseline value.

Calcium, potassium, chloride, magnesium, carbon dioxide content/bicarbonate, sodium and urea/BUN were measured at Baseline, Day 3 and Day 5 during the treatment period. The baseline assessments were referred to assessments at Day 1. Change from Baseline was calculated as the value at the indicated time point minus the Baseline value.

Percentages of basophils, eosinophils, lymphocytes, monocytes and total neutrophils were measured at Baseline, Day 3 and Day 5 during the treatment period. The baseline assessments were referred to assessments at Day 1. Change from Baseline was calculated as the value at the indicated time point minus the Baseline value.

WBC and platelet counts were measured at Baseline, Day 3 and Day 5 during the treatment period. The baseline assessments were referred to assessments at Day 1. Change from Baseline was calculated as the value at the indicated time point minus the Baseline value.

Hemoglobin was measured at Baseline, Day 3 and Day 5 during the treatment period. The baseline assessments were referred to assessments at Day 1. Change from Baseline was calculated as the value at the indicated time point minus the Baseline value.

Hematocrit was measured at Baseline, Day 3 and Day 5 during the treatment period. The baseline assessments were referred to assessments at Day 1. Change from Baseline was calculated as the value at the indicated time point minus the Baseline value.

The reference ranges for clinical chemistry parameters were ALT 5 to 45 IU/L, ALP 100 to 325 IU/L, creatine kinase 60 to 270 IU/L, AST 10 to 40 IU/L, creatinine 41.548 to 69.836 µmol/L, direct bilirubin 0 to 5.13 µmol/L, total bilirubin 3.42 to 20.52 µmol/L, calcium 2.0958 to 2.5948 mmol/L, CO2/ bicarbonate 19.2 to 27.1 mmol/L, chloride 98 to 108 mmol/L, magnesium 0.7809 to 1.0275 mmol/L, potassium 3.5 to 5 mmol/L, sodium 137 to 147 mmol/L and urea/ BUN 2.856 to 8.211 mmol/L. The baseline assessments were referred to assessments at Day 1. Number of participants with shifts between normal range (NR) high, within NR and NR low values in hematology parameters from baseline (Day 1) at Day 3 and Day 5 is reported.

The reference ranges for hematology parameters were basophils 0 to 2%, eosinophils 0 to 8%, lymphocytes 18 to 49%, monocytes 2 to 10%, total neutrophils 40 to 75%, platelet count 140 to 340 GI/L, WBC count 3.3 to 9 GI/L, hemoglobin 135 to 175 g/L and haematocrit 0.397 to 0.524 ratio. The baseline assessments were referred to assessments at Day 1. Number of participants with shifts between NR high, within NR and NR low values in hematology parameters from baseline (Day 1) at Day 3 and Day 5 is reported.

The normal reference ranges for clinical chemistry and hematology parameters were ALT 5 to 45 IU/L, ALP 100 to 325 IU/L, creatine kinase 60 to 270 IU/L, AST 10 to 40 IU/L, creatinine 41.548 to 69.836 µmol/L, direct bilirubin 0 to 5.13 µmol/L, total bilirubin 3.42 to 20.52 µmol/L, calcium 2.0958 to 2.5948 mmol/L, CO2/ bicarbonate 19.2 to 27.1 mmol/L, chloride 98 to 108 mmol/L, magnesium 0.7809 to 1.0275 mmol/L, potassium 3.5 to 5 mmol/L, sodium 137 to 147 mmol/L, urea/ BUN 2.856 to 8.211 mmol/L, basophils 0 to 2%, eosinophils 0 to 8%, lymphocytes 18 to 49%, monocytes 2 to 10%, total neutrophils 40 to 75%, platelet count 140 to 340 GI/L, WBC count 3.3 to 9 GI/L, hemoglobin 135 to 175 g/L and haematocrit 0.397 to 0.524 ratio. Participants with treatment emergent toxicities for grade 3 (severe) and grade 4 (potentially life threatening) were assessed at Day 1, Day 3 and Day 5. Classification of the toxicities as potentially drug-related was done based on the investigator's judgment.

Vital sign of HR was assessed three times daily during the treatment period/hospitalization at Day 1, Day 2, Day 3, Day 4, Day 5 and Day 6. The baseline assessments were referred to assessments at Day 1. Maximum value in a day is reported where a 'day' is defined as a 24 h period (Treatment Day).

Vital signs of SBP and DBP were assessed three times daily during the treatment period/hospitalization at Day 1, Day 2, Day 3, Day 4, Day 5 and Day 6. The baseline assessments were referred to assessments at Day 1. Minimum value in a day for SBP is reported where a 'day' is defined as a 24 h period (Treatment Day). DBP is measured at the same time as minimum SBP.

Vital signs of OS was assessed three times daily during the treatment period/hospitalization at Day 1, Day 2, Day 3, Day 4, Day 5 and Day 6. The baseline assessments were referred to assessments at Day 1. Minimum value in a day is reported, where a 'day' is defined as a 24 h period (Treatment Day).

Vital signs of RR was assessed three times daily during the treatment period/hospitalization at Day 1, Day 2, Day 3, Day 4, Day 5 and Day 6. The baseline assessments were referred to assessments at Day 1. Maximum value in a day is reported, where a 'day' was defined as a 24 h period (Treatment Day).

Vital signs of temperature was assessed three times daily during the treatment period/hospitalization at Day 1, Day 2, Day 3, Day 4, Day 5 and Day 6. The baseline assessments were referred to assessments at Day 1. Maximum value in a day is reported, where a'day' was defined as a 24 h period (Treatment Day).

12-lead ECG assessments were obtained at Baseline (Day 1) and Day 4 of the treatment period. On Baseline (Day 1), 2 baseline ECGs were obtained prior to study drug infusion. On Day 4, 2 ECGs were obtained, 1 ECG just prior to study drug infusion and 1 ECG at the end of infusion. Overall ECG findings were summarized with regard to visits at Day 1 (pre-dose \[ECG 1 and ECG 2\]) and Day 4 (pre-dose and 30-min post dose).

12-lead ECG assessments were obtained at Baseline (Day 1) and Day 4 of the treatment period. On Baseline (Day 1), 2 baseline ECGs were obtained. On Day 4, 2 ECGs were obtained, 1 ECG just prior to study drug infusion and 1 ECG at the end of infusion. Overall ECG findings were summarized at Day 1 (ECG 1 and ECG 2) and Day 4 (pre-dose and 30-min post dose).

Clinical response is defined as the resolution of at least 4 of the 5 vital signs (temperature, oxygen saturation, respiratory status, heart rate, systolic blood pressure) within the respective resolution criteria, maintained for at least 24 hours, or hospital discharge, whichever occurred first. This analysis was performed for Influenza positive population, for those with symptom onset less than or equal to (\<=) 4 days, and for those on mechanical (mech) ventilation or in intensive care unit (ICU). 99 days is censored time for the participants who did not achieve TTCR.

Blood samples will be collected at indicated time points for pharmacokinetic analysis of zanamivir.

Blood samples will be collected at indicated time points for pharmacokinetic analysis of zanamivir.

Blood samples will be collected at indicated time points for pharmacokinetic analysis of zanamivir.

Blood samples will be collected at indicated time points for pharmacokinetic analysis of zanamivir.

PK parameter assessed following single dose administration include the observed maximum serum drug concentration (Cmax), time to reach Cmax (tmax), elimination half-time (t1/2), area under the concentration-time curve from administration extrapolated to the last time of quantifiable concentration (AUC \[0-t\]), area under the concentration-time curve from administration extrapolated to 12 hours of quantifiable concentration (AUC \[0-12\]), area under the concentration-time curve from time zero extrapolated to infinite time (AUC \[0-infinity\]), clearance (CL) and volume of distribution after intravenous administration (Vz).

PK parameter assessed following repeat dose administration include Cmax, pre-dose trough concentration (Ctau), tmax, t1/2, AUC (0-t), area under the concentration-time curve during steady state (AUC \[0-tau\]), CL, Vz, volume of distribution after intravenous administration at steady state (Vss), observed accumulation ratios (Ro) and time invariance ratio (Rs).