Abnormal XYY karyotype; Foetal exposure during pregnancy; This is a serious observational study case, initially received from other health professional on 20-Sep-2019, concerning a foetal subject. The mother was 34-year-old female subject of body weight:120 Ibs, height: 64 inches and body mass index (BMI): 20.6, enrolled in, a study on pregnancy outcomes in women immunized with seasonal cell culture influenza trivalent (TIVc) or quadrivalent (QIVc) vaccine during pregnancy.  The mother' current condition included gas. The mother's concomitant medication included: Citrinatal assure (ascorbic acid, calcium citrate, colecalciferol, cupric oxide, docosahexaenoic acid, docusate sodium, eicosapentaenoic acid, folic acid, iron, nicotinamide, potassium iodide, pyridoxine hydrochloride, riboflavin, thiamine, tocopheryl acetate, zinc oxide) for healthy pregnancy, simethicone for gas and Makena (hydroxyprogesterone caproate) to reduce risk of preterm birth.  The mother's obstetrical history included two previous pregnancies with one full term live birth and one preterm live birth. The mother had no maternal or paternal history with major congenital malformations. The mother did not use tobacco, alcohol or illicit drugs during pregnancy. The mother's last menstrual period (LMP) date was on 03-Sep-2018 and the pregnancy was singleton. The estimated delivery date (EDD) was 10-Jun-2019.  On 11-Oct-2018, at five weeks of gestation, the mother was administered Flucelvax QIVc [influenza vaccine, subunit influenza virus vaccine polyvalent, batch number: 252232, dose: 0.5 ml, route of administration, anatomical location, expiry date: not reported) (explicitly coded as Foetal exposure during pregnancy') for influenza immunisation.  On 27-Nov-2018, the mother underwent First trimester screening test and risk of Down syndrome was identified.  On 06-Dec-2018, the mother underwent Non-invasive prenatal testing (NIPT) and abnormal XYY karyotype was identified.  On 11-Dec-2018, at 14.1 weeks of gestation, the mother underwent elective termination and it was reported as patient choice'. No further information was provided.  This case is linked to 201805974, corresponding mother case.  Company Comment: Foetal subject was diagnosed with XYY syndrome after foetal exposure during pregnancy, at gestation age of 5 weeks with the suspect product Flucelvax QIVc. Temporal relationship is implausible because the event occurred at the time of conception and before administration of the suspect product. The mother underwent elective termination of pregnancy. Foetal exposure during pregnancy is assessed as not related per company conventions. For the event XYY syndrome, causal role of the suspect product is assessed as not related.; Reporter's Comments: Foetal subject was diagnosed with XYY syndrome after foetal exposure during pregnancy, at gestation age of 5 weeks with the suspect product Flucelvax QIVc. Temporal relationship is implausible because the event occurred at the time of conception and before administration of the suspect product. The mother underwent elective termination of pregnancy. Foetal exposure during pregnancy is assessed as not related per company conventions. For the event XYY syndrome, causal role of the suspect product is assessed as not related.