Premature delivery at 36.4 weeks of gestation; Herpes type 2; Vaccine exposure during pregnancy; Acid reflux; This is an observational study case, received on 07-Aug-2019 from other health professional and concerned a 20-year-old, pregnant, female subject of body weight 97 lbs, height 60 inches and body mass index (BMI) 18.9, enrolled in, a prospective observational safety study.   The subject's past medical history included bacterial vaginosis (from 07-Sep-2018 to 16-Sep-2018). The subject's concurrent condition included muscle spasms. The subject's concomitant medications included Prenatal vitamins (mineral nos, vitamins nos) for pregnancy, Metrogel (metronidazole) for bacterial vaginosis and ciclopirox for muscle spasms.   The subject's obstetrical history noted that the subject had no previous pregnancies. The subject did not have a history of offspring with major congenital malformations (MCMs). Also, the subject had no maternal or paternal history with MCMs. The subject did not use alcohol or illicit drugs during pregnancy. The subject used cigarettes during pregnancy (one pack per day).   The subject's last menstrual period (LMP) date was 01-Mar-2018. Estimated delivery date (EDD) and corrected estimated date of delivery (CEDD) were reported as 06-Dec-2018. The type of pregnancy was singleton.   On 30-Aug-2018, spinal muscular atrophy test and cystic fibrosis mutation analysis revealed no MCMs.   On 10-Sep-2018, ultrasound revealed no MCM.   On 08-Oct-2018, at gestational age of 31 weeks (calculated per LMP), the subject was vaccinated with Flucelvax QIVc (Flu Vaccine Cell Subunit QIV NVD) [influenza vaccine, subunit influenza virus vaccine polyvalent, dose: 0.5 ml, route of administration and anatomical location: not reported) (explicitly coded as vaccine exposure during pregnancy') for influenza immunisation. The batch number reported was 252664.   On the same day, after receiving Flucelvax QIVc, the subject developed acid reflux and started treatment with Zantac (ranitidine hydrochloride), at a dose of one tablet administered via oral route, once per day.   On 22-Oct-2018, a toxoplasmosis, rubella, cytomegalovirus, herpes simplex, and HIV (TORCH) panel test and ultrasound revealed no MCMs.    On 26-Oct-2018, 18 days after vaccination, the subject developed herpes type 2. It was not reported whether the subject received any corrective treatment for the event.  On 30-Oct-2018, ultrasound revealed no MCM.   On 11-Nov-2018, at gestational age of 36.4 weeks (as reported), the subject vaginally delivered live birth, male neonate. The neonate's birth weight was 2041 g, head circumference and length were not reported. The appearance, pulse, grimace, activity and respiration (APGAR) scores were 8 (one minute) and 9 (five minutes). APGAR score was not reported for 10 minutes. No major congenital malformation was identified at birth.  On 07-Aug-2019, the subject completed the study and the registry was closed as no additional information was expected.   At the time of follow up reporting on 17-Sep-2020, the subject had not recovered from the events of acid reflux and herpes simplex type II'.  The reporter did not provide a causality assessment.   The event of premature delivery' was considered to be medically significant by a Physician within Seqirus' Pharmacovigilance and Risk Management Department.  This case is linked to 201904364, the corresponding child report.  Non-significant additional information received on 04-Sep-2019 from other health professional: It was confirmed that the events 'herpes simplex' and 'acid reflux' were still ongoing. No change in the narrative.  Additonal information received on 17-Sep-2020 from other health professional: The subject's age was updated from 21 to 20 years. Fetal outcome changed from normal to perinatal complication in pregnancy information. Six laboratory tests coded in laboratory data. Concomitant medications details updated. The event of premature delivery' was marked as medically significant and the case was upgraded to serious. Stop date added for the events of premature delivery' and vaccine exposure during pregnancy'. Outcome changed from not reported' to resolved' for vaccine exposure during pregnancy'. Date of study completion was provided. number removed as reference number. The narrative was amended accordingly.  Company comment: The patient experienced herpes simplex type II 18 days after vaccination and premature delivery 1 month 3 days after vaccination with Flu Vaccine Cell Subunit QIV NVD. The patient also developed gastroesophageal reflux disease on the same day after vaccination with the suspect product, administered at 31 weeks of gestation. Chronology is plausible. Although causality for gastroesophageal reflux disease was highly confounded by pregnancy, causal role of the suspect vaccine cannot be totally excluded and is assessed as unlikely related. (defaults to "related" in the safety database for reporting purposes). The patient's medical history of muscle spasms, and especially tobacco use may have contributed to the event of premature delivery. Causality is assessed as not related. For the event of herpes simplex type II, causality is assessed as not related due to biological implausibility. Vaccine exposure during pregnancy is assessed as not related per company's conventions.; Sender's Comments: The patient experienced herpes simplex type II 18 days after vaccination and premature delivery 1 month 3 days after vaccination with Flu Vaccine Cell Subunit QIV NVD. The patient also developed gastroesophageal reflux disease on the same day after vaccination with the suspect product, administered at 31 weeks of gestation. Chronology is plausible. Although causality for gastroesophageal reflux disease was highly confounded by pregnancy, causal role of the suspect vaccine cannot be totally excluded and is assessed as unlikely related. (defaults to "related" in the safety database for reporting purposes). The patient's medical history of muscle spasms, and especially tobacco use may have contributed to the event of premature delivery. Causality is assessed as not related. For the event of herpes simplex type II, causality is assessed as not related due to biological implausibility. Vaccine exposure during pregnancy is assessed as not related per company's conventions.