A Study to Assess Safety, Tolerability and Immunogenicity of RSVpreF From Multidose Vials in Healthy Female Adults.

GMTs and corresponding 2-sided 95% confidence intervals (CIs) were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution).

Time frame: Before vaccination on Day 1

Population: Evaluable immunogenicity population (EIP): all eligible participants who received the study intervention to which they were randomized, had blood drawn for assay testing within the specified time frame (27 to 42 days after vaccination) for 1 month after vaccination, had at least 1 valid and determinate assay result at the 1-month follow-up visit, and had no major protocol violations. Here, Number Analyzed signifies participants evaluable for specified rows.

GMTs and corresponding 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution). GMTs of NTs for RSV A and B were reported in the descriptive data section of this outcome measure. GMR each for RSV A and RSV B was calculated as ratio of NTs of RSVpreF (MDV) to RSVpreF (SDV) and was reported in the statistical analysis section of this outcome measure.

Time frame: 1 month after Vaccination on Day 1

Population: EIP: all eligible participants who received the study intervention to which they were randomized, had blood drawn for assay testing within the specified time frame (27 to 42 days after vaccination) for 1 month after vaccination, had at least 1 valid and determinate assay result at the 1-month follow-up visit, and had no major protocol violations. Here, Overall Number of Participants Analyzed signifies number of participants evaluable for this outcome measure.

An AE was defined as any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention were included in evaluation of this outcome measure. AEs included both serious AEs (SAEs) and all non-SAEs. Events collected by systematic assessment (local reactions and systemic events) were excluded from evaluation.

Time frame: Within 1 Month after Vaccination

Population: Safety population consisted of all randomized participants who received study intervention.

Local reactions included redness, swelling and pain at injection site, reported in the electronic diary (e-diary) and the participant-reported reactogenicity (PARREACT) case report form (CRF). Redness and swelling were measured and recorded in measuring device units, where 1 measuring device unit= 0.5 centimeter (cm) and graded as mild: \>2.0 to 5.0 cm, moderate: \>5.0 to 10.0 cm, severe: \>10.0 cm, Grade 4: necrosis (redness and swelling) or exfoliative dermatitis (redness). Pain at injection site was graded as mild: did not interfere with activity, moderate: interfered with activity, severe: prevented daily activity, Grade 4: emergency room visit or hospitalization for severe pain at injection site.

Time frame: Day 1 through Day 7 after Vaccination

Population: Safety population consisted of all randomized participants who received study intervention.

An AEs was defined as any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention. An SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect and other important medical events per protocol of the study. Events collected by systematic assessment (local reactions and systemic events) were excluded from evaluation.

Time frame: Within 42 to 49 days after Vaccination on Day 1 (maximum up to 1.6 months)

Population: Safety population consisted of all randomized participants who received study intervention.

Systemic events included fever, fatigue, headache, vomiting, nausea, diarrhea, muscle pain and joint pain, recorded in the e-diary and PARREACT CRF. Fever measured in degree Celsius and ranged: mild (38.0 - 38.4); moderate (38.5 - 38.9); severe (39.0 - 40.0); Grade 4: \>40.0. Fatigue, headache, nausea, muscle and joint pain graded as: mild (didn't interfere with activity); moderate (some interference with activity); severe (prevented daily routine activity); Grade 4 \[emergency room (ER) visit or hospitalization). Vomiting graded as: mild (1-2 times in 24 hours\[h\]); moderate (\>2 times in 24h); severe (required intravenous hydration); Grade 4 (ER visit or hospitalization). Diarrhea graded as: mild (2-3 loose stools in 24h); moderate (4-5 loose stools in 24h); severe (6 or more loose stools in 24h); Grade 4 (ER visit or hospitalization).

Time frame: Day 1 through Day 7 after Vaccination

Population: Safety population consisted of all randomized participants who received study intervention.

Seroresponse was defined as achieving a \>=4-fold rise from baseline (before vaccination) if the baseline measurement was above the lower limit of quantification (LLOQ). If the baseline measurement was below the LLOQ, a postvaccination assay result \>=4\*LLOQ was considered a seroresponse.

Time frame: 1 Month after Vaccination

Population: EIP was analyzed. Here, Overall Number of Participants Analyzed = number of participants evaluable for this outcome measure and Number Analyzed = number of participants evaluable for specified rows.