GMTs of pre-F antibodies as assessed by ELISA at 14 days post administration of Ad26/protein preF RSV based vaccine were reported.

The per-protocol immunogenicity (PPI) set included all randomized participants who received the study vaccine, and for whom immunogenicity data were available.

Number of participants with solicited local AEs 7 days post vaccination on Day 1 were reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Solicited local AEs were precisely defined events that participants were specifically asked about and which were noted by participants in the diary. Solicited local AEs that included injection site pain/tenderness, erythema and swelling at the study vaccine injection site, were used to assess the reactogenicity of the study vaccine and were pre-defined local (injection site).

The full analysis set (FAS) included all participants who received study vaccination, regardless of the occurrence of protocol deviations. Here, 'N' (number of participants analyzed) signifies participants evaluable for this outcome measure.

Number of participants with solicited systemic AEs 7 days post vaccination on Day 1 were reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Solicited systemic events included events such as fatigue, headache, nausea, and myalgia, for which participants were specifically questioned and which were noted by participants in their participant diary for 7 days post vaccination (day of vaccination and the subsequent 7 days).

The FAS included all participants who received study vaccination, regardless of the occurrence of protocol deviations. Here, 'N' (number of participants analyzed) signifies participants evaluable for this outcome measure.

Number of participants with unsolicited AEs 28 days post vaccination on Day 1 were reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Unsolicited AEs were all AEs for which the participant was not specifically questioned in the participant diary.

The FAS included all participants who received study vaccination, regardless of the occurrence of protocol deviations.

Number of participants with SAEs until 6 months post vaccination on Day 1 were reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. An SAE is any untoward medical occurrence that at any dose may result in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is a suspected transmission of any infectious agent via a medicinal product.

The FAS included all participants who received study vaccination, regardless of the occurrence of protocol deviations.

Number of participants with AESIs until 6 months post vaccination on Day 1 were reported. An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Thrombosis with thrombocytopenia syndrome (TTS) was considered as an AESI.

The FAS included all participants who received study vaccination, regardless of the occurrence of protocol deviations.

RSV A2 strain neutralizing antibody titers of the vaccine-induced immune response was assessed through virus neutralization assay at 14 days post administration of Ad26/protein preF RSV based vaccine were expressed as 50 percent (%) inhibitory concentration (IC50) units.

The PPI set included all randomized participants who received the study vaccine, and for whom immunogenicity data were available.