A Study to Evaluate the Efficacy, Safety, and Pharmacokinetics of Subcutaneously Administered Guselkumab for the Treatment of Chronic Plaque Psoriasis in Pediatric Participants

Inclusion Criteria: * Have a diagnosis of chronic plaque-type psoriasis for at least 6 months (with or without psoriatic arthritis \[PsA\]), prior to first administration of study intervention, defined as having at screening and baseline, Investigator Global Assessment (IGA) greater than or equal to (\>=) 3, Psoriasis Area and Severity Index (PASI) \>=12, \>=10% body surface area (BSA) involvement and at least one of the following: very thick lesions, clinically relevant facial, genital, or hand/ foot involvement, PASI\>=20, \>20% BSA involvement, or IGA=4 * Be a candidate for phototherapy or systemic treatment of plaque psoriasis (either naive or history of previous treatment) * Have plaque psoriasis considered by the investigator as inadequately controlled with phototherapy and/or topical therapy after an adequate dose and duration of therapy * Be considered, in the opinion of the investigator, a suitable candidate for etanercept therapy, according to their country's approved Enbrel product labeling * Be otherwise healthy on the basis of physical examination, medical history, and vital signs performed at screening. Any abnormalities, must be consistent with the underlying illness in the study population and this determination must be recorded in the participant's source documents and initialed by the investigator * Must have acceptable evidence of immunity to varicella and measles, mumps, and rubella (MMR), which includes any one of the following: documentation of age-appr…