This literature marketed report as received from the authors of published literature article refers to an unknown number of infant patients of unknown age and gender. The background of the article was a concern for respiratory decompensation after immunization in premature infants, particularly those with bronchopulmonary dysplasia (BPD), that might have lead to delayed and altered immunization schedules. The objectives of the study were to determine if infants with BPD experience respiratory decompensation after immunization in greater proportion than those infants without BPD and to explore patient characteristics that may predispose infants to respiratory decompensation after immunization. The authors also sought to evaluate whether these patients have a clinically relevant concern for apnea, bradycardia and desaturation (A/B/D) events after immunization. A method was a retrospective observation of a cohort of premature infants at <32 weeks' gestational age cared for in a tertiary level 4 neonatal intensive care unit (NICU) between 01-JAN-2008 and 01-AUG-2014 and immunized during their hospital stay who were evaluated for respiratory decompensation within 72 hours of immunization. Respiratory measurements including change in respiratory support, mean fraction of inspired oxygen, and apnea, bradycardia, and desaturation events were compared between those infants with BPD and those without. There were 68 patients in the no BPD group with 93 immunization events. On unknown dates during the 6.5-years retrospective study period from 01-JAN-2008 and 01-AUG-2014, the patients were vaccinated with PEDVAXHIB (dose, route, lot # and expiry date were not provided). Other suspect vaccinations included ROTATEQ oral vaccine (dose, lot # and expiry date were not provided), IPOL (dose and route were not provided), INFANRIX (dose and route were not provided), ENGERIX-B (dose and route were not provided), PCV13 (dose and route were not provided), FLUZONE (dose and route were not provided) and PEDIARIX (dose and route were not provided), all administered on unknown dates during the 6.5-years retrospective study period in accordance to recommended immunization schedule. Twelve patients were immunized at <36 weeks' cGA, 5 of these 12 patients were receiving respiratory support at the time of immunization but had been weaned off respiratory support by 36 weeks' cGA. On unknown dates within 72 hours of immunizations, 5 patients of 68 experienced respiratory decompensation which was an increase in respiratory support defined as a change to any greater level of respiratory support (categorized as follows in increasing level: low-flow nasal cannula (LFNC) defined as flow <2 L/minute, high-flow nasal cannula (HFNC) defined as flow >=2 L/minute, continuous positive airway pressure (CPAP), noninvasive positive-pressure ventilation, and conventional mechanical ventilation (CMV) as delivered by endotracheal intubation). On unknown dates within 72 hours of immunizations, 23 patients of 68 developed increased A/B/D events. Apnea was defined as cessation of respiration for >=20 seconds, bradycardia as a decrease in heart rate to <=100 beats per minute for a period of >=20 seconds, and desaturations as an oxygen saturation via pulse oximetry of <88%. A/B/D episodes were obtained from the chart as documented by nursing staff for a 72-hour period before and after immunization. Most of these events were benign and resolved without significant clinical intervention. The final outcome of the events was however unknown. There was an increase in A/B/D events after immunizations. The author considered the events to be related to the vaccinations with PEDVAXHIB, ROTATEQ, IPOL, INFANRIX, ENGERIX-B, PCV13, FLUZONE AND PEDIARIX. Upon internal review the events of apnoea, bradycardia and respiratory decompensation were considered to be medically significant. This is one of the two reports from the same literature article (MARRS #1606USA005552). Additional information has been requested.