Did a flu test and determined type A flu; Fever; Fatigue; Type A flu; Vaccination failure; This is a spontaneous case, initially received from other non-health professional (consumer) on 08-Feb-2019, concerning a 35-year-old, adult female patient.   The patient had no historical conditions. The patient's concomitant medications included Multivitamins (vitamins nos) and Vitamin C (ascorbic acid).   On 09-Oct-2018, the patient was administered Flucelvax QIVc [influenza vaccine, subunit influenza virus vaccine polyvalent, cell-culture-derived, dose: 0.5 ml, route of administration: intramuscular, anatomical location: deltoid, batch number: 252664 and expiry date: 30-Jun-2019] for active immunization against influenza.  On 03-Feb-2019, 3 months and 25 days after vaccination, the patient experienced fatigue and an unspecified symptom of flu (explicitly coded as vaccination failure). On 05-Feb-2019, 3 months and 27 days after vaccination, the patient experienced fever. The patient was treated with Tylenol (paracetamol) for fever, but the fever did not subside. Hence, she went to the emergency room on 06-Feb-2019. The doctor at the emergency room performed a flu test and determined that the patient had type A flu (explicitly coded as vaccination failure). The patient also took Sudafed (pseudoephedrine hydrochloride). The patient was outside of the window to take Tamiflu and hence, she was not prescribed with it. On 08-Feb-2019, the patient stopped taking the treatment medications.  The patient had recovered from the events on 14-Feb-2019. The outcome of the events (vaccination failure and influenza A virus test positive) was unknown.  This case was associated with product quality complaint, hence quality assurance investigation (QAI) had been requested and the corresponding QAIR reference number was 1039510. Based on the investigation performed, it can be concluded that Flucelvax 252664 was manufactured in compliance with the approved internal procedures and in accordance with the quality requirements. No evidence was found that the lack of efficacy complaint was the result of the Fill Finish or Bulk manufacturing process at the facility and no trend was identified for the batch. Therefore, no internal root cause could be confirmed.   The reporter assessed the case as non-serious.  Follow-up received from the other non-health professional on 01-Mar-2019: The stop date (08-Feb-2019) of the treatment drug was added in the product tab. The stop date (08-Feb-2019) of the event fever was added in the event tab and the outcome was changed from recovering to recovered. The new event fatigue was added in the event tab. The narrative and was amended accordingly.  Follow-up received from the other non-health professional on 11-Mar-2019: The reporter had not provided any institution name and patient's title. The outcome of the event influenza was recovered and the stop date for all the events was 14-Feb-2019. The start date (03-Feb-2019) of the symptom (fatigue) was added in event tab. The stop date of the event fever was changed from '08-Feb-2019' to 14-Feb-2019' in event tab. The med info number (SEQ19-01031) was added in the additional information. The narrative was amended accordingly.  Follow up report received from Quality assurance department on 28-Mar-2019: This case was associated with product quality complaint, hence quality assurance investigation (QAI) had been requested and the corresponding QAIR reference number was 1039510. Based on the investigation performed, it can be concluded that Flucelvax 252664 was manufactured in compliance with the approved internal procedures and in accordance with the quality requirements. The narrative was amended accordingly.; Reporter's Comments: A 35-year-old female patient was diagnosed with Influenza type A, more than 3 months after receipt of Flucelvax QIVc (considered as vaccination failure). The diagnosis was confirmed by flu test. Time to onset is plausible following vaccination with the reported Influenza type A and vaccination failure events. Hence, company assessed the events as possibly related to suspect vaccine.  The company assessed the case as serious (medically significant).