In the controlled and non-controlled portions of psoriasis clinical studies, the rate of infection was 1.24 per patient-year of follow-up in ustekinumab-treated patients, and the incidence of serious infections was 0.01 per patient-year of follow-up in ustekinumab-treated patients (24 serious infections in 2,251 patient-years of follow-up) and serious infections reported included cellulitis, diverticulitis, osteomyelitis, viral infections, gastroenteritis, pneumonia, and urinary tract infections.