Initial unsolicited misuse report received from the literature on 20 June 2016. Abstract Background: Approaches to improve the immune response of immunocompromised patients to influenza vaccination are needed. Methods: Children and young adults (3-21 years) with cancer or HIV infection were randomized to receive 2 doses of high-dose (HD) trivalent influenza vaccine (TIV) or of standard-dose (SD) TIV. Hemagglutination inhibition (HAI) antibody titers were measured against H1, H3, and B antigens after each dose and 9 months later. Seroconversion was defined as greater than or equal to 4-fold rise in HAI titer comparing pre- and post-vaccine sera. Seroprotection was defined as a post-vaccine HAI titer greater than or equal to 1:40. Reactogenicity events (RE) were solicited using a structured questionnaire 7 and 14 days after each dose of vaccine, and adverse events by medical record review for 21 days after each dose of vaccine. Results: Eighty-five participants were enrolled in the study; 27 with leukemia, 17 with solid tumor (ST), and 41 with HIV. Recipients of HD TIV had significantly greater fold increase in HAI titers to B antigen in leukemia group and to H1 antigen in ST group compared to SD TIV recipients. This increase was not documented in HIV group. There were no differences in seroconversion or seroprotection between HD TIV and SD TIV in all groups. There was no difference in the percentage of solicited RE in recipients of HD TIV (54% after dose 1 and 38% after dose 2) compared to SD TIV (40% after dose 1 and 20% after dose 2, p=0.27 and 0.09 after dose 1 and 2, respectively). Conclusion: HD TIV was more immunogenic than SD TIV in children and young adults with leukemia or ST, but not with HIV. HD TIV was safe and well-tolerated in children and young adults with leukemia, ST, or HIV. This case involves a 09-year-old male patient who was vaccinated with first dose of FLUZONE HD (batch number, dose, dose in series, site of administration were not reported) intramuscularly on an unknown date (in 2011-12) in the afternoon after recovery from sedation. The patient's medical history included non-Hodgkin lymphoma and neurological disorder who underwent sedation for a routine imaging study before vaccination. Concomitant medications were not reported. On an unknown date, approximately 4 hours following the vaccination (6 hours after discharged), the patient had increased sleepiness or Grade 2 somnolence and was taken to hospital again and hospitalized for testing and observation. It was inappropriate age at vaccine administration, Drug use in unapproved population and off label use. Relevant laboratory test results included electroencephalography, CT scan, and neurological examination have been unremarkable. The patient's corrective treatment was not reported. On an unknown date, the patient was recovered from the events (within 2-3 hours) and was discharged from the hospital. Documents held by sender: none. Sender's Comments: This case refers to a 9 years old male child, a known case of non-Hodgkin lymphoma who received INFLUENZA USP TRIVAL A-B HIGH DOSE SUBVIRION VACCINE and 6 hours later experienced Grade 2 Somnolence. Time to onset is compatible with the role of vaccine. In this particular case, patient has history of neurological disorder (details not provided). Based on the available information, further investigations such as electroencephalography, CT scan, and neurological examinations were performed and had unremarkable findings (detailed results were not provided). In the absence of any alternative explanation and considering the positive temporal relationship, causality for the reported events with the suspect vaccine cannot be excluded.