Partial placenta previa; Herpes simplex virus 2 outbreak; Nausea; Vaccine exposure during pregnancy; This is an observational study case, initially received from other health professional on 02-Jan-2020, concerning a 33-year-old pregnant, female subject of body weight 147.5 lbs, height 63 inches and body mass index (BMI) 26.1 enrolled in a prospective observational safety study.  The subject's medical history included seasonal allergies, herpes simplex virus 2 and increased BMI.  The subject's concomitant medications included Prenatal gummy (unspecified vitamins and minerals) for pregnancy and Zyrtec (cetirizine hydrochloride) for seasonal allergies.  The subject's obstetrical history included one previous full-term live birth. The subject had no history of offspring with major congenital malformation (MCM), nor relevant maternal and paternal medical history. The subject did not consume tobacco, alcohol and illicit drugs during pregnancy.  The subject's last menstrual period (LMP) date was 20-Sep-2019. The type of pregnancy was singleton. The subject's estimated delivery date (EDD) and corrected estimated date of delivery (CEDD) were both reported as 26-Jun-2020.   On 12-Nov-2019, the subject underwent ultrasound scan and no MCM was noted.  On 18-Nov-2019, at gestational age of eight weeks (calculated per LMP), the subject was administered Afluria Quadrivalent (Flu Vaccine Egg Split QIV CSL) [influenza vaccine, batch number: P100126099, dose, route of administration, anatomical location and expiration date: not reported] for influenza immunisation (explicitly coded as 'Vaccine exposure during pregnancy') as influenza immunisation.  On 19-Dec-2019, approximately one month after vaccination, the subject experienced nausea and had an outbreak of herpes simplex virus 2. On the same day, the subject started treatment for herpes simplex virus 2 outbreak with Valtrex (valaciclovir hydrochloride) at a dose of 500 mg, administered via oral route, two times per day for 3 days and treatment for nausea with Bonjesta (doxylamine succinate, pyridoxine hydrochloride) at a dose 20 mg, administered via oral route, two times per day.  On 21-Dec-2019, the treatment with Valtrex was discontinued and the outcome of herpes simplex virus 2 outbreak was resolved.  On 03-Feb-2020, the subject underwent ultrasound and partial placenta previa was noted. No MCM was noted.  At the time of this follow up, the outcome of partial placenta previa was not reported, while the outcome of nausea was not resolved.  The event of placenta previa' was considered serious due to the criterion of medical significance.  The reporter did not provide a causality assessment to Afluria QIV.  Follow up received from other health professional on 10-Jan-2020: The start and stop dates for herpes simplex virus 2 outbreak provided. The outcome of herpes simplex virus 2 outbreak updated. The start date for nausea provided. Narrative amended accordingly.  Follow up received from other health professional on 17-Mar-2020: The lab data updated. The event of partial placenta previa was added and accordingly case was upgraded from non-serious to serious. It was confirmed that outcome of nausea was not resolved. Narrative amended accordingly.  Company comment: The subject experienced Herpes simplex reactivation and nausea after vaccination with the suspect product, Afluria QIV. Placenta praevia was noted 2 months and 16 days post vaccination. Reportedly, vaccination occurred during pregnancy at 8 weeks of gestation. Chronology is plausible. Pregnant state may provide alternative aetiology for the events. Medical history of previous herpes simplex virus 2, increased body mass index and concomitant medication, Zyrtec (cetirizine hydrochloride) may have also contributed to development of the events. Vaccine exposure during pregnancy is assessed as not related per company's conventions. Causality between suspect product and the events is assessed as unlikely related (defaults to related for reporting purposes).; Sender's Comments: The subject experienced Herpes simplex reactivation and nausea after vaccination with the suspect product, Afluria QIV. Placenta praevia was noted 2 months and 16 days post vaccination. Reportedly, vaccination occurred during pregnancy at 8 weeks of gestation. Chronology is plausible. Pregnant state may provide alternative aetiology for the events. Medical history of previous herpes simplex virus 2, increased body mass index and concomitant medication, Zyrtec (cetirizine hydrochloride) may have also contributed to development of the events. Vaccine exposure during pregnancy is assessed as not related per company's conventions. Causality between suspect product and the events is assessed as unlikely related (defaults to related for reporting purposes).