Suspected vaccination failure; Influenza B; Severe acute respiratory infection; This case was reported in a literature article and described the occurrence of vaccination failure in a patient who received Flu unspecified (Flu vaccine) for prophylaxis.   Co-suspect products included Flu unspecified (Influenza vaccine) for prophylaxis.   On an unknown date, the patient received the 2nd dose of Flu vaccine and the 1st dose of Influenza vaccine. On an unknown date, less than 2 years after receiving Flu vaccine and Influenza vaccine, the patient experienced vaccination failure (serious criteria hospitalization and GSK medically significant), influenza b virus infection (serious criteria hospitalization) and acute respiratory tract infection (serious criteria hospitalization). On an unknown date, the outcome of the vaccination failure, influenza b virus infection and acute respiratory tract infection were unknown.   The reporter considered the vaccination failure, influenza b virus infection and acute respiratory tract infection to be related to Flu vaccine and Influenza vaccine.     Additional Information: GSK Receipt Date: 10-OCT-2022 Author comment: The case was created from table 3 given in the article. The patient was a part of study which analyzed data from four countries participating in a multicentre, test-negative design, vaccine effectiveness network including 41 sentinel hospitals. Individuals hospitalized at one of these centres with severe acute respiratory infection were tested for influenza by real-time RT-PCR, and were included in the analysis if they had complete information about their vaccination status and outcomes of their hospital stay. 2747 patients hospitalized with PCR-confirmed influenza virus infection between Jan 1, 2013, and Dec 8, 2019, were included in the study: 649 children (70 [10o8%] fully vaccinated, 193 [29o7%] partially vaccinated) of whom 87 (13o4%) were admitted to ICU and 12 (1o8%) died in hospital; 520 adults with pre-existing medical conditions (118 [22o7%] vaccinated), of whom 139 (26o7%) were admitted to ICU and 55 (10o6%) died in hospital; and 1578 older adults (609 [38o6%] vaccinated), of whom 271 (17o2%) were admitted to ICU and 220 (13o9%) died in hospital. For children aged 6 to 24 months, the participants were categorized as fully vaccinated if they had received two doses of influenza vaccine at least 14 days before symptom onset; and partially vaccinated if they had received only one dose of influenza vaccine at least 14 days before symptom onset. 12 (1o8%) of 649 children aged 6 to 24 months died in hospital: eight (2o1%) of 386 unvaccinated children, three (1o5%) of 193 partially vaccinated children, and one (1o4%) of 70 fully vaccinated children died in hospital. The patient's age was 6 to 24 months. The patient was fully vaccinated and had received two doses of influenza vaccine at least 14 days before symptom onset. The patient was hospitalized and real time Reverse transcription polymerase chain reaction (RT-PCR) of nasal or nasopharyngeal swab was performed and confirmed influenza B infection.  Based on sentinel surveillance, the results indicated that influenza vaccination could offer health benefits to some patients hospitalized with breakthrough influenza virus infections. A shorter lengths of hospital stay among partially and fully vaccinated children aged 6 to 24 months and vaccinated adults aged 18 to 64 years with pre-existing medical conditions compared with unvaccinated individuals in the respective age groups was observed. Influenza vaccination was associated with illness attenuation among those hospitalized with influenza, although results differed by vaccine target group. These findings might suggest that attenuation of disease severity might be specific to certain target groups, seasons, or settings.' Additional supportive information: This case was considered to be a suspected vaccination failure case, as the details regarding time to onset was unknown. This is 1 of the 3 cases reported in this Literature article.; Sender's Comments:  US-GLAXOSMITHKLINE-US2022GSK147321:Same author