This is a serious spontaneous case, initially received from other health professional on 15-May-2019, concerning a male neonate patient. The patient's mother was a 37-year-old who had 2 previous pregnancies (gravida II) and had 2 previous preterm live births. The patient's mother did not use tobacco, alcohol or illicit drugs during pregnancy. The current conditions of the patient's mother included frequent urinary tract infections and herpes simplex virus infection (HSV). The concomitant medications of patient's mother included MACROBID for urinary tract infections and prenatal vitamins for pregnancy. The mother's last menstrual period (LMP) date was 13-Jul-2018. The type of pregnancy was singleton. On 07-Sep-2018, mother's ultrasound was performed, and no major congenital malformation was noted. On 13-Sep-2018, mother's prenatal blood work, haemoglobin electrophoresis and cystic fibrosis mutation analysis performed, and no major congenital malformation was noted. On 08-Oct-2018, mother's non-invasive prenatal testing (NIPT) performed, and no major congenital malformation was noted. On 01-Nov-2018, at gestation age of 16 weeks (second trimester), the patient's mother was administered Flu Vaccine Egg Split QIV CSL (batch number: YF41708, dose: 0.5 ml, route of administration, anatomical location and expiry date: not reported) for an unknown indication. The foetus was exposed to AFLURIA QIV via transplacental route of administration for an unknown indication. On 12-Nov-2018, maternal serum alpha-fetoprotein (MSAFP)/serum markers test was performed, and no congenital malformation was noted. On 26-Nov-2018, ultrasound was performed, and anatomic scan revealed amniotic band across cervix, but the foetus was free of band. On 18-Dec-2018, genitourinary condition- herpes simplex virus (HSV) was noted in the patient's mother. The patient's mother took Valacyclovir HCl for herpes simplex virus (HSV). On 14-Jan-2019, the patient's mother underwent 1-hour glucose tolerance test (GTT) was found to be normal. 4 months and 8 days after vaccination, the mother delivered a male neonate at 34.1 weeks gestation (premature birth) by caesarean method of delivery. The neonate birth weight was 2741 grams and head circumference was 33 cm. The appearance, pulse, grimace, activity, and respiration (APGAR) scores were 7 (one minute), 7 (five minutes) and 8 at ten minutes. There was no major congenital malformation noted. The outcome of the event (premature birth) was unknown. This case is linked to 201805325 (mother case). Reporter's Comments: A male neonate was delivered at 34.1 weeks gestation (premature birth) by caesarean method, 4 months and 8 days after administration of AFLURIA QIV vaccine given at 16 weeks of gestational age. Considering there is no evidence for a biological mechanism that could cause the event, maternal risk factors (advanced gestational age - 37 years, 2 previous preterm live births, frequent urinary tract infections, herpes simplex virus and concomitant drugs - valacyclovir and clarithromycin), the event was assessed as not related to the suspect vaccine. The decision to administer a vaccine during pregnancy is related to medical decision making by the mother and her physician and is not related to any property of the medication. The event of foetal exposure during pregnancy was assessed as not related considering the intended use of the vaccine. This company assessed this case as serious (medically significant). The company assessed the event premature birth as serious (medically significant).