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 adult patient who received Flu unspecified (Flu vaccine) for prophylaxis.  On an unknown date, the patient received Flu vaccine. On an unknown date, unknown after receiving Flu 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.   Additional Information: GSK Receipt Date: 10-OCT-2022 Author comment: The case was created from table 1 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 the purpose of study, the adults aged 18 years or older were considered as vaccinated if they had a record of vaccination with the southern hemisphere formulation of influenza vaccine at least 14 days before symptom onset. Of the 520 adults aged 18-64 years with pre-existing medical conditions and hospitalized with influenza, 139 (26o7%) were admitted to ICU and 55 (10o6%) died in hospital. 118 (22o7%) were vaccinated against influenza. Vaccination status was associated with sex (p=0o0061), pre-existing asthma (p less than 0o0001) or renal conditions (p=0o0218), previous vaccination against influenza (p less than 0o0001), and number of pre-existing medical conditions (p=0o0425), with the vaccinated group having a higher proportion of patients with 3 or more pre-existing medical conditions than the unvaccinated group.  The patient received influenza vaccine at least 14 days before symptom onset and had severe acute respiratory infection. 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 length 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