A Study of Ustekinumab in Pediatric Participants With Moderately to Severely Active Crohn's Disease

Inclusion Criteria: * Have Crohn's disease or fistulizing Crohn's disease with active colitis, ileitis, or ileocolitis, confirmed at any time in the past by endoscopy and histology * Must have moderately to severely active Crohn's disease (as defined by a baseline Pediatric Crohn's Disease Activity Index \[PCDAI\] score greater than \[\>\] 30); have ileocolonoscopy with evidence of active Crohn's disease defined as presence of ulceration (which is equal to Simple Endoscopic Score for Crohn's disease \[SES-CD\] score greater than or equals to \[\>=\] 3) during screening into this study. The ileocolonoscopy procedure must occur within approximately 3 weeks prior to the administration of study intervention at Week 0 (Induction Period). A video ileocolonoscopy recorded within 3 months prior to the Week 0 (Induction Period) visit may be used in case of rescreening of a participant who had an ileocolonoscopy but failed the initial screening for another reason, on a case-by-case basis, after consultation with the sponsor. If unable to evaluate ulceration due to stricture or inadequate bowel preparation, at least one of the following criteria may instead be applied: an abnormal C-reactive protein (CRP) (\> 0.3 milligram per deciliter \[mg/dL\] or 3.0 milligram per liter \[mg/L\] at screening) or; fecal calprotectin of \>= 250 milligram per kilogram \[mg/kg\] or \>= 250 microgram per gram \[mcg/g\] at screening * If receiving enteral nutrition, must have been on a stable regimen for …