A Study of an Ad26.RSV. preF-based Vaccine in Adults Aged 18 to 59 Years, Including Adults at High Risk for Severe RSV Infection

Inclusion Criteria: * Participants must be of a) non child bearing potential or b) of child bearing potential and practicing an acceptable and effective of contraception * All participants of childbearing potential must: have a negative highly sensitive urine beta-human chorionic gonadotropin (beta-hCG) pregnancy test at screening; and have a negative highly sensitive urine beta-hCG pregnancy test immediately prior to each study vaccination (if screening and vaccination are not performed on the same day) Cohorts 1 and 2 * Participant is aged 18 to 59 years (inclusive) on the day of signing the informed consent form (ICF) and expected to be available for the duration of the study Cohort 2 * Has an existing chronic heart or lung condition, without hospitalizations or major medication class change (that is, new or stopped medications) within 30 days prior to screening, meeting the following criteria; a) cardiac disease: at least Class II symptoms per New York Heart Association classification or similar guidelines according to local practice, b) pulmonary disease: activity-restricting symptoms or use of long-term medications Cohort 3 * Participant is aged 65 years or older on the day of signing the ICF and expected to be available for the duration of the study * Participant may have underlying illnesses such as hypertension, congestive heart failure, chronic obstructive pulmonary disease (COPD), type 2 diabetes, hyperlipoproteinemia, or hypothyroidism, as long as their symptoms …