Assessed solicited systemic events include fatigue, headache, gastrointestinal (GI) symptoms (nausea, vomiting, diarrhea, abdominal pain) and fever. The preferred location for measuring temperature was the oral cavity. Fever was defined as temperature equal to or above (≥) 38.0 °C/ 100.4°F. This objective analyzed the safety and reactogenicity of RSV MAT vaccine when given alone (pooled lots) or co-administered with Flu D-QIV. As pre-specified in protocol, data reported in this outcome measure was presented for the pooled RSV and RSV+Flu groups and Flu+Placebo Group, since minimal differences were expected between participants who received different RSV lots of the vaccine.