A Study to Evaluate Different Dose Levels of Ad26.COV2.S in Healthy Adolescents From 12 to 17 Years Inclusive

Available safety, immunogenicity and efficacy data from the Ad26.COV2.S vaccine development program supports initiating evaluation of Ad26.COV2.S in the pediatric population. Ad26.COV2.S will be evaluated in the pediatric population through a dose-confirmation approach. Ad26.COV2.S (also known as Ad26COVS1, VAC31518, JNJ-78436735) is a monovalent vaccine composed of a recombinant, replication-incompetent human adenovirus type 26 (Ad26) vector, constructed to encode the severe acute respiratory syndrome coronavirus(-2) (SARS-CoV-2) spike (S) protein, stabilized in its prefusion conformation. The study duration from screening until the last follow-up visit will be, excluding the 28-day screening phase, 8 months (Groups 4-6) to 12 months (Groups 1-3), consisting of 12-month study duration comprising a study period (6-months) including vaccination with a 1 active dose and a placebo vaccination (56-day interval), followed by a booster vaccination at 6 months and follow-up (safety and immunogenicity) until at least 6 months after booster vaccination (Groups 1-3) and 8 month study duration comprising 2 active doses (56-day interval) and follow-up (safety and immunogenicity) until at least 6 months after second vaccination (Groups 4-6). Assessments like immunogenicity (such as humoral and cellular immune responses), safety and reactogenicity (such as adverse events [AEs] monitoring) will be performed in this study. Other safety assessments include vital signs measurements (heart rate, supine systolic and diastolic blood pressure, respiratory rate, and body temperature) and physical examinations. The overall study duration from enrolment of the first participant until study completion is expected to be up to 1 year 11 months.