This is a serious spontaneous case, initially received from other non-healthcare professional on 26-Mar-2018, concerning a 16-year-old, adolescent, male patient. The patient had no medical history and concurrent conditions. The patient did not receive any concomitant medications. It was reported that, patient was healthy prior to vaccination. On 18-Oct-2017, the patient was administered with FLUCELVAX QIV [dose: 0.5 ml (reported as 0.5 mg), route of administration: intramuscular, anatomical location: right deltoid, batch number: 195250 and expiry date: not reported]. On 24-Mar-2018, the patient felt ill with the complaints of headache, nausea (occurred once) and fatigue. On the same day, after 5 months 7 days of vaccination, nasal swab test was done, and the patient was diagnosed with Influenza A virus infection. The patient contacted the doctor on 26-Mar-2018. The patient was not treated with any anti-viral drugs as he was ill for several days. This case was associated with product quality complaint, hence quality assurance investigation (QAI) had been requested and the corresponding QAI reference number was 1029003. The investigation performed concluded that FLUCELVAX 195250 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 trends were identified for the batch, or any other FLUCELVAX QIV batches from the 2017-2018 FLUCELVAX Commercial season. Therefore, no internal root cause could be performed. On 29-Mar-2018, the patient had recovered from headache, nausea (occurred once), fatigue and Influenza A virus infection. Non-significant follow-up received from quality assurance department on 30-Mar-2018: This case was associated with product quality complaint, hence product technical complaint (PTC) had been requested and the corresponding PTC reference number was 1029003. Follow-up received from quality assurance department on 07-Apr-2018: The investigation performed concluded that FLUCELVAX 195250 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 trends were identified for the batch, or any other FLUCELVAX QIV batches from the 2017-2018 FLUCELVAX Commercial season. Therefore, no internal root cause could be confirmed. Narrative was amended accordingly. Follow-up report received on 27-Apr-2018: On an unspecified date in Mar-2018 (reported as, roughly on 24-Mar-2018), the patient felt ill with the complaints of headache, nausea (occurred once) and fatigue. Hence, onset date of the event influenza was updated (unspecified date in Mar-2018). The patient contacted the doctor on 26-Mar-2018 and continued to feel unwell until about the 29-Mar-2018. Follow-up report received on 10-May-2018: The reporter confirmed that, on 24-Mar-2018 the patient felt ill with the complaints of headache, nausea (occurred once), fatigue and Influenza A virus infection. On 29-Mar-2018, the patient had recovered from the events headache, nausea (occurred once), fatigue and Influenza A virus infection (added in the event tab). The narrative was amended accordingly.