Relapse of bipolar depression; Aches and pains; Ringing in her ears; Joint pain / Burning pains in her small joints; Myalgia; This literature case was received on 07-Jun-2021 and concerned a 49-year-old, female patient.  The patient's concurrent conditions included well controlled bipolar depression and comorbid attention-deficit / hyperactivity disorder. The patient's concomitant medications included buspirone, lurasidone, oxcarbazepine and trazodone, all for bipolar depression and lisdexamfetamine for comorbid attention-deficit / hyperactivity disorder.  On an unspecified date, two weeks earlier, the patient's depression was in full remission and she had scored 0 on the 9-item Patient Health Questionnaire (PHQ-9).   On an unknown date, a week before coming to clinic, the patient was vaccinated with influenza virus vaccine polyvalent (brand not specified; dose, route of administration, indication and anatomical location: not reported). The batch number was not reported.   On the same day, within a couple of hours after receiving influenza virus vaccine polyvalent, the patient started feeling depressed and became tearful. These symptoms were followed a couple of days later with aches and pains, which escalated over the subsequent days. She complained of joint pain, burning pains in her small joints and myalgia, and rated her pain as 6/10.   On an unspecified date, two weeks after her clinic visit, the patient returned to the clinic for an urgent, unscheduled visit due to escalating depression, which was rated as 18/27 on the PHQ-9 (a score of 15-19 was considered moderately severe). The patient also noticed ringing in her ears for the previous two days. On the assumption that patient's relapse of depression was related to an immune response, physicians agreed to a trial of celecoxib at dose of 200 mg twice a day and she was asked to return in a week if her condition did not improve.   On an unknown date, the patient started treatment with celecoxib for relapse of bipolar depression.   On an unknown date, the patient's depression resolved when treated with celecoxib.  On an unknown date, eight weeks later, the patient returned to clinic for a previously scheduled appointment and reported having experienced a dramatic response to celecoxib. Her depression had remitted rapidly, and she scored 0/27 on the PHQ-9. The patient reported an additional benefit of improved interpersonal interactions.   The outcome of 'pain', joint pain and myalgia was not reported.   The author assessed the event of bipolar depression as related to influenza virus vaccine polyvalent, while the causality for other events was not provided. Physicians discussed the possibility that patient's depression might be a reaction to the flu vaccine. On the assumption that her relapse of depression was related to an immune response they agreed to a trial of celecoxib. Should bipolar patients experience vaccination-induced relapse of depression, adding celecoxib to their treatment regimen could be helpful.  The event of bipolar depression was considered to be medically significant by a Physician within Seqirus' Pharmacovigilance and Risk Management Department.   Company comment: A 49-year-old, female patient with medical history of well controlled bipolar depression and comorbid attention-deficit / hyperactivity disorder was vaccinated with influenza virus vaccine polyvalent. On the same day, within a couple of hours after receiving influenza virus vaccine polyvalent, the patient started feeling depressed and became tearful. These symptoms were followed a couple of days later with aches and pains, which escalated over the subsequent days. She complained of joint pain, burning pains in her small joints and myalgia. On an unspecified date, two weeks after her clinic visit, the patient returned to the clinic for an urgent, unscheduled visit due to escalating depression. The patient also noticed ringing in her ears. On the assumption that patient's relapse of depression was related to an immune response, physicians agreed to a trial of celecoxib at dose of 200 mg twice a day. The patient's concomitant medications included buspirone, lurasidone, oxcarbazepine and trazodone. Causal role of the suspect vaccine cannot be  excluded and is assessed as possibly related for all events.; Reporter's Comments: Physicians discussed the possibility that patient's depression might be a reaction to the flu vaccine. On the assumption that her relapse of depression was related to an immune response they agreed to a trial of celecoxib. Should bipolar patients experience vaccination-induced relapse of depression, adding celecoxib to their treatment regimen could be helpful.; Sender's Comments: A 49-year-old, female patient with medical history of well controlled bipolar depression and comorbid attention-deficit / hyperactivity disorder was vaccinated with influenza virus vaccine polyvalent. On the same day, within a couple of hours after receiving influenza virus vaccine polyvalent, the patient started feeling depressed and became tearful. These symptoms were followed a couple of days later with aches and pains, which escalated over the subsequent days. She complained of joint pain, burning pains in her small joints and myalgia. On an unspecified date, two weeks after her clinic visit, the patient returned to the clinic for an urgent, unscheduled visit due to escalating depression. The patient also noticed ringing in her ears. On the assumption that patient's relapse of depression was related to an immune response, physicians agreed to a trial of celecoxib at dose of 200 mg twice a day. The patient's concomitant medications included buspirone, lurasidone, oxcarbazepine and trazodone. Causal role of the suspect vaccine cannot be  excluded and is assessed as possibly related for all events.