OBJECTIVES: The patient voice is an essential component in vaccine outcomes evaluation. To date there are no standard clinical outcome assessment tools to measure RSV-associated symptoms or activities of daily living (ADLs) impacts that include the patient perspective. A patient-reported outcomes measure (PROM) was developed to assess RSV symptom intensity and impact (RSV-iiiQ) in adults. METHODS: Initial draft RSV-iiiQ questions were adapted from the Influenza Intensity and Impact Questionnaire (Flu-iiQ: a well-developed and tested PROM to assess influenza severity), and then modified based on relevance to RSV infection in accordance with results from a literature review and clinical expert input. Next, qualitative interviews were conducted with adults with laboratory-confirmed RSV infection to assess concepts and item relevance/understanding, response options, instructions, and recall period. Additionally, usability via an electronic format was evaluated. RESULTS: The draft RSV-iiiQ included 29 questions evaluating symptoms and impacts over a 24-hour recall using a four-point response scale from none to severe or no to severe difficulty. Twenty adults were interviewed. Mean age was 52 years (range: 26-78); 70% were female. Fourteen reported moderate symptom severity. Feedback informed minor revisions to question wording to enhance understanding. Participants endorsed inclusion of all candidate concepts and found them relevant and meaningful. Examples included respiratory symptoms (cough, runny nose), systemic symptoms (fatigue, headache, fever), impact on ADLs (difficulty with preparing/getting food, self-care), and impact on emotions (helplessness, frustration). The electronic format was deemed easy to use. CONCLUSIONS: Qualitative interview results supported content validity of the RSV-iiiQ in adults. Research is underway to assess psychometric measurement properties. The final measure, including both patient and clinical perspectives, may be useful in evaluations of RSV vaccine efficacy and effectiveness.