Fever (oral temperature >= 38 degC) was categorized as >=38.0-38.4 degC, >38.4-38.9 degC, >38.9-40.0 degC and >40.0 degC. Decreased appetite was graded as mild: decreased interest in eating, moderate: decreased oral intake, severe: refusal to feed. Drowsiness was graded as mild: increased/prolonged sleeping bouts, moderate: slightly subdued, interfered daily activity, severe: disabled, not interested in daily activity. Irritability was graded as mild: easily consolable, moderate: required increased attention, severe: inconsolable, crying couldn't be comforted. Grade 4 decreased appetite, drowsiness and irritability events led to emergency room visit or hospitalization and were classified by investigator/medically qualified person. Any systemic event: any fever, decreased appetite, drowsiness, irritability.

An AE was any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. Results excluded local reactions and systemic events data.

An AE was any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was an AE that resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or nonpathogenic; other situations as judged by investigator.

Predefined IgG concentrations was >= 0.35 micrograms per milliliter (mcg/mL).

Predefined level of IgG concentrations was >= 0.35 mcg/mL.

GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the student-t distribution).

GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the student-t distribution).

GMTs and the corresponding 2-sided CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on student's t distribution).

GMTs and the corresponding 2-sided CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on student's t distribution).

GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the student-t distribution).

GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the student-t distribution).

Participants who had previously received 2 doses of PCV10 primary series as part of their infant routine vaccines were administered 0.5 mL dose of mPnC control intramuscularly at Visit 1 of the study (Day 1 of study; Dose 1) and Visit 3 of the study (56 to 70 days after Visit 1; Dose 2). Participants also received their third (toddler) dose of PCV10 at Visit 1 per childhood vaccine standard of care.

Total of all reporting groups

Local reactions included redness, swelling and pain at injection site. Redness and swelling were graded as mild: > 0 to 2.0 cm, moderate: >2.0 to 7.0 cm, severe: >7.0 cm and Grade 4: necrosis or exfoliative dermatitis (redness) and necrosis (swelling). Pain at injection site was graded as mild: hurt if gently touched, moderate: hurt if gently touched, with crying, severe: caused limitation of limb movement and Grade 4 (potentially life threatening): emergency room visit or hospitalization for severe pain at injection site. Grade 4 assessments were made by the investigator. Any local reaction: any mild, moderate, severe, or Grade 4 redness, swelling, or pain at the injection site.

Safety analysis set included all participants who received at least 1 dose of the study intervention. Here, ''Overall Number of Participants Analyzed'' signifies participants who received Dose 2 and who were evaluable for this outcome measure.

Fever (oral temperature >= 38 degree Celsius [degC]) was categorized as >=38.0-38.4 degC, >38.4-38.9 degC, >38.9-40.0 degC and >40.0 degC. Decreased appetite was graded as mild: decreased interest in eating, moderate: decreased oral intake, severe: refusal to feed. Drowsiness was graded as mild: increased/prolonged sleeping bouts, moderate: slightly subdued, interfered daily activity, severe: disabled, not interested in daily activity. Irritability was graded as mild: easily consolable, moderate: required increased attention, severe: inconsolable, crying couldn't be comforted. Grade 4 decreased appetite, drowsiness and irritability events led to emergency room visit or hospitalization and were classified by investigator/medically qualified person. Any systemic event: any fever, decreased appetite, drowsiness, irritability.

Safety analysis set included all participants who received at least 1 dose of the study intervention. Here, ''Overall Number of Participants Analyzed'' signifies participants who received Dose 1 and who were evaluable for this outcome measure.

Fever (oral temperature >= 38 degC) was categorized as >=38.0-38.4 degC, >38.4-38.9 degC, >38.9-40.0 degC and >40.0 degC. Decreased appetite was graded as mild: decreased interest in eating, moderate: decreased oral intake, severe: refusal to feed. Drowsiness was graded as mild: increased/prolonged sleeping bouts, moderate: slightly subdued, interfered daily activity, severe: disabled, not interested in daily activity. Irritability was graded as mild: easily consolable, moderate: required increased attention, severe: inconsolable, crying couldn't be comforted. Grade 4 decreased appetite, drowsiness and irritability events led to emergency room visit or hospitalization and were classified by investigator/medically qualified person. Any systemic event: any fever, decreased appetite, drowsiness, irritability.

Safety analysis set included all participants who received at least 1 dose of the study intervention. Here, ''Overall Number of Participants Analyzed'' signifies participants who received Dose 2 and who were evaluable for this outcome measure.

An AE was any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. Results excluded local reactions and systemic events data.

Safety analysis set included all participants who received at least 1 dose of the study intervention. Here, ''Overall Number of Participants Analyzed'' signifies participants who received Dose 1 and who were evaluable for this outcome measure.

An AE was any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. An SAE was an AE that resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or nonpathogenic; other situations as judged by investigator.

Safety analysis set included all participants who received at least 1 dose of the study intervention. Here, ''Overall Number of Participants Analyzed'' signifies participants who received Dose 1 and who were evaluable for this outcome measure.

GMCs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the concentrations and the corresponding CIs (based on the student t distribution).

Dose 1 evaluable immunogenicity population included all participants who were eligible and randomized, received the study intervention to which they were randomized, had at least 1 valid immunogenicity result within 27 to 56 days, inclusive, after Dose 1, and had no other major protocol deviations as determined by the clinician up to the 1-month post-Dose 1 visit.

GMCs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the concentrations and the corresponding CIs (based on the student t distribution).

Dose 2 evaluable immunogenicity population included all participants who were eligible and randomized, received both doses of study intervention to which they were randomly assigned, had at least 1 valid immunogenicity result within 27 to 56 days, inclusive, after Dose 2, and had no other major protocol deviations as determined by the clinician up to the 1-month post-Dose 2 visit.

Predefined IgG concentrations was >= 0.35 micrograms per milliliter (mcg/mL).

Dose 1 evaluable immunogenicity population included all participants who were eligible and randomized, received the study intervention to which they were randomized, had at least 1 valid immunogenicity result within 27 to 56 days, inclusive, after Dose 1, and had no other major protocol deviations as determined by the clinician up to the 1-month post-Dose 1 visit.

Predefined level of IgG concentrations was >= 0.35 mcg/mL.

Dose 2 evaluable immunogenicity population included all participants who were eligible and randomized, received both doses of study intervention to which they were randomly assigned, had at least 1 valid immunogenicity result within 27 to 56 days, inclusive, after Dose 2, and had no other major protocol deviations as determined by the clinician up to the 1-month post-Dose 2 visit.

GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the student-t distribution).

Dose 1 evaluable immunogenicity population included all participants who were eligible and randomized, received study intervention to which they were randomized, had at least 1 valid immunogenicity result within 27 to 56 days, inclusive, after Dose 1, and had no other major protocol deviations as determined by clinician up to 1-month post-Dose 1 visit. Here, ''Overall Number of Participants Analyzed'' signifies Dose 1 evaluable participants with valid result at both timepoints.

GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the student-t distribution).

Dose 2 evaluable immunogenicity population included all participants who were eligible, randomized, received both doses of study intervention to which they were randomly assigned, had at least 1 valid immunogenicity result within 27 to 56 days, inclusive, after Dose 2, had no major protocol deviations as determined by clinician up to 1-month post-Dose 2 visit. Here, ''Overall Number of Participants Analyzed'' signifies Dose 2 evaluable participants with valid result at both timepoints.

GMTs and the corresponding 2-sided CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on student's t distribution).

Dose 1 evaluable immunogenicity population included all participants who were eligible and randomized, received study intervention to which they were randomized, had at least 1 valid immunogenicity result within 27 to 56 days, inclusive, after Dose 1, and had no other major protocol deviations as determined by clinician up to 1-month post-Dose 1 visit. Here, ''Overall Number of Participants Analyzed'' signifies Dose 1 evaluable participants with valid OPA titers.

GMTs and the corresponding 2-sided CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on student's t distribution).

Dose 2 evaluable immunogenicity population included all participants who were eligible, randomized, received both doses of study intervention to which they were randomly assigned, had at least 1 valid immunogenicity result within 27 to 56 days, inclusive, after Dose 2, had no major protocol deviations as determined by clinician up to 1-month post-Dose 2 visit. Here, ''Overall Number of Participants Analyzed'' signifies Dose 2 evaluable participants with valid OPA titers.

GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the student-t distribution).

Dose 1 evaluable immunogenicity population included all participants who were eligible and randomized, received study intervention to which they were randomized, had at least 1 valid immunogenicity result within 27 to 56 days, inclusive, after Dose 1, and had no other major protocol deviations as determined by clinician up to 1-month post-Dose 1 visit. Here, ''Overall Number of Participants Analyzed'' signifies Dose 1 evaluable participants with valid OPA result at both timepoints.

GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the student-t distribution).

Dose 2 evaluable immunogenicity population included all participants who were eligible, randomized, received both doses of study intervention to which they were randomly assigned, had at least 1 valid immunogenicity result within 27 to 56 days, inclusive, after Dose 2, had no major protocol deviations as determined by clinician up to 1-month post-Dose 2 visit. Here, ''Overall Number of Participants Analyzed'' signifies Dose 2 evaluable participants with valid OPA result at both timepoints.

Participants who had previously received 2 doses of PCV10 primary series as part of their infant routine vaccines were administered 0.5 mL dose of mPnC control intramuscularly at Visit 1 of the study (Day 1 of study; Dose 1) and Visit 3 of the study (56 to 70 days after Visit 1; Dose 2). Participants also received their third (toddler) dose of PCV10 at Visit 1 per childhood vaccine standard of care.