Assessed solicited local AEs are erythema, pain and swelling at injection site. Any = occurrence of the adverse event regardless of intensity grade. Any redness and swelling = adverse event reported with a surface diameter greater than 0 millimeters. Analysis of this outcome measure were reported for the RSV1D pooled, RSV2D pooled, active comparators pooled and placebo groups separately to compare the expected adverse events observed from routine pediatric vaccines (active comparators) with the investigational RSV vaccine. Placebo was not pooled with active comparators as no significant difference was expected in AEs when placebo was pooled with active comparators. As pre-specified in the protocol, the choice of active comparator or placebo was based on each participating country's standard of care.

Analysis of this outcome measure were reported for the RSV1D pooled, RSV2D pooled, active comparators pooled and placebo groups separately to compare the expected adverse events observed from routine pediatric vaccines (active comparators) with the investigational RSV vaccine. Placebo was not pooled with active comparators as no significant difference was expected in AEs when placebo was pooled with active comparators. As pre-specified in the protocol, the choice of active comparator or placebo was based on each participating country's standard of care.

Assessed solicited general adverse events are drowsiness, fever \[defined as temperature equal to or above (\>=) 38.degrees Celsius (C)/100.4 Fahrenheit (F) by any route\], irritability/fussiness and loss of appetite. Any = occurrence of the adverse event regardless of intensity grade or relation to study vaccination. Analysis of this outcome measure were reported for the RSV1D pooled, RSV2D pooled, each of the active comparators and placebo groups separately as the study interest was to investigate solicited AEs during the follow-up period of RSV vaccine administration, compared to placebo and routine pediatric vaccines, especially comparing to the rates of Bexsero-related fever. As pre-specified in the protocol, the choice of active comparator or placebo was based on each participating country's standard of care.

Analysis of this outcome measure were reported for the RSV1D pooled, RSV2D pooled, each of the active comparators and placebo groups separately as the study interest was to investigate solicited AEs during the follow-up period of RSV vaccine administration, compared to placebo and routine pediatric vaccines, especially comparing to the rates of Bexsero-related fever. As pre-specified in the protocol, the choice of active comparator or placebo was based on each participating country's standard of care.

An unsolicited AE covers any untoward medical occurrence in a clinical investigation subject temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. Unsolicited AEs are reported in addition to those solicited during the clinical study and any solicited symptom with onset outside the specified period of follow-up for solicited symptoms. Any was defined as the occurrence of any unsolicited AE regardless of intensity grade or relation to study vaccination. Analysis of this outcome measure were reported for the RSV1D pooled, RSV2D pooled, and comparator\_placebo pooled groups as data collection was based on different standard of care provided at participating countries rather than randomization to each of the individual groups. According to the pre-specified analysis plan, data collected for participant flow, baseline characteristics and adverse events reporting were not analyzed for the individual groups.

Assessed serious adverse events (SAEs) include medical occurrences that resulted in death, were life-threatening, required hospitalization or prolongation of hospitalization or resulted in disability/incapacity. Any = occurrence of SAE regardless of intensity grade or relation to study vaccination. Analysis of this outcome measure were reported for the RSV1D pooled, RSV2D pooled, and comparator\_placebo pooled groups as data collection was based on different standard of care provided at participating countries rather than randomization to each of theindividual groups. According to the pre-specified analysis plan, data collected for participant flow, baseline characteristics and adverse events reporting were not analyzed for the individual groups.

Any episode of spontaneous or excessive bleeding if occurring after vaccination was to be fully investigated with a full range of hematological tests to identify the underlying cause and reported as an AE of special interest. Analysis of this outcome measure were reported for the RSV1D pooled, RSV2D pooled, and comparator\_placebo pooled groups as data collection was based on different standard of care provided at participating countries rather than randomization to each of the individual groups. According to the pre-specified analysis plan, data collected for participant flow, baseline characteristics and adverse events reporting were not analyzed for the individual groups.

Assessed solicited local symptoms are pain, redness and swelling at injection site. Any = occurrence of the symptom regardless of intensity grade. Any redness and swelling symptom = symptom reported with a surface diameter greater than 0 millimeters.

Assessed solicited general symptoms are drowsiness, fever \[defined as temperature equal to or above (≥) 37.5 degrees Celsius (°C)/99.5 degrees Fahrenheit (°F) for oral, axillary or tympanic route, or ≥ 38.0°C/100.4°F for rectal route, the preferred route for recording temperature in this study being axillary\], irritability/fussiness and loss of appetite. Any = occurrence of the symptom regardless of intensity grade or relation to study vaccination.

Any episode of spontaneous or excessive bleeding if occurring after vaccination was to be fully investigated with a full range of hematological tests to identify the underlying cause and reported as an AE of specific interest.

Assessed hematological laboratory parameters include hemoglobin level \[HgL\] white blood cells \[WBC\] and platelet count \[PLC\]. Hematological abnormalities refer to range indicator at timing, categorized as Below, Within or Above normal ranges, and compared to baseline range indicator of the same parameter, at Screening (Day-29 to Day 1) i.e. Unknown, Below, Within or Above. \[e.g. HgL, Below, Below = HgL below normal ranges at baseline versus below normal ranges at Day 2\].

Assessed hematological laboratory parameters include hemoglobin level \[HgL\] white blood cells \[WBC\] and platelet count \[PLC\]. Hematological abnormalities refer to range indicator at timing, categorized as Below, Within or Above normal ranges, and compared to baseline range indicator of the same parameter, at Screening (Day-29 to Day 1) i.e. Below, Within or Above. \[e.g. HgL, Below, Below = HgL below normal ranges at baseline versus below normal ranges at Day 8\].

Assessed hematological laboratory parameters include hemoglobin level \[HgL\] white blood cells \[WBC\] and platelet count \[PLC\]. Hematological abnormalities refer to range indicator at timing, categorized as Below, Within or Above normal ranges, and compared to baseline range indicator of the same parameter, at Screening (Day-29 to Day 1) i.e. Unknown, Below, Within or Above. \[e.g. HgL, Below, Below = HgL below normal ranges at baseline versus below normal ranges at Day 31\].

Assessed hematological laboratory parameters include hemoglobin level \[HgL\] white blood cells \[WBC\] and platelet count \[PLC\]. Hematological abnormalities refer to range indicator at timing, categorized as Below, Within or Above normal ranges, and compared to baseline range indicator of the same parameter, at Screening (Day-29 to Day 1) i.e. Unknown, Below, Within or Above. \[e.g. HgL, Below, Below = HgL below normal ranges at baseline versus below normal ranges at Day 32\].

Assessed hematological laboratory parameters include hemoglobin level \[HgL\] white blood cells \[WBC\] and platelet count \[PLC\]. Hematological abnormalities refer to range indicator at timing, categorized as Below, Within or Above normal ranges, and compared to baseline range indicator of the same parameter, at Screening (Day-29 to Day 1) i.e. Below, Within or Above. \[e.g. HgL, Below, Below = HgL below normal ranges at baseline versus below normal ranges at Day 38\].

Assessed hematological laboratory parameters include hemoglobin level \[HgL\] white blood cells \[WBC\] and platelet count \[PLC\]. Hematological abnormalities refer to range indicator at timing, categorized as Below, Within or Above normal ranges, and compared to baseline range indicator of the same parameter, at Screening (Day-29 to Day 1) i.e. Unknown, Below, Within or Above. \[e.g. HgL, Below, Below = HgL below normal ranges at baseline versus below normal ranges at Day 61\].

Assessed biochemical laboratory parameters include alanine aminotransferase \[ALT\], aspartate aminotransferase \[AST\] and creatinine \[CREA\]. Biochemical abnormalities refer to range indicator at timing, categorized as Below, Within or Above normal ranges, and compared to baseline range indicator of the same parameter, at Screening (Day-29 to Day 1) i.e. Unknown, Below, Within or Above. \[e.g. ALT, Below, Below = ALT below normal ranges at baseline versus below normal ranges at Day 31\].

Assessed biochemical laboratory parameters include alanine aminotransferase \[ALT\], aspartate aminotransferase \[AST\] and creatinine \[CREA\]. Biochemical abnormalities refer to range indicator at timing, categorized as Below, Within or Above normal ranges, and compared to baseline range indicator of the same parameter, at Screening (Day-29 to Day 1) i.e. Below, Within or Above. \[e.g. ALT, Below, Below = ALT below normal ranges at baseline versus below normal ranges at Day 61\].