Upper respiratory infection; Vaccine exposure during pregnancy; This is an observational study case, initially received from other health professional on 02-Dec-2019, concerning a 34-year-old, female pregnant subject of body weight: 185 lbs, height: 63.6 inches and body mass index (BMI): 32.2 enrolled in, a prospective observational safety study.  The subject's current conditions included advanced maternal age and obesity.   The subject's concomitant medication included Prenatal vitamins (unspecified minerals and vitamins) for pregnancy.  The subject's obstetrical history included one previous pregnancy with one full term live birth baby. The subject had no history of offspring with major congenital malformation (MCM) and no relevant maternal and paternal medical history. The subject did not use tobacco, alcohol or illicit drugs during pregnancy. The subject's last menstrual period (LMP) date was 07-Jun-2019. The subject's estimated delivery date (EDD) and corrected estimated date of delivery (CEDD) were 13-Mar-2020. The type of pregnancy was singleton.  On 08-Aug-2019, the subject underwent ultrasound and no MCM was noted.  On 22-Aug-2019, the subject underwent Maternit 21 test and no MCM was noted.  On 03-Oct-2019, the subject underwent second trimester screen and mother's serum alpha fetoprotein (MSAFP) / serum markers and no MCM was noted.  On 24-Oct-2019, at gestational age at 19 weeks, the subject was administered Flucelvax QIVc [influenza vaccine, subunit influenza virus vaccine polyvalent, batch number: 261223, dose: 0.5 ml, anatomical location, route of administration and expiration date: not reported] (explicitly coded as Vaccine exposure during pregnancy') for an influenza immunisation. On the same day, the subject underwent anatomy ultrasound and no MCM was noted.  On 19-Nov-2019, 26 days after vaccination, the subject developed upper respiratory infection. The subject was treated with Zithromax z-pack(azithromycin), at a dose of 250 mg, orally, frequency reported as two tablets once daily (qd) and one tablet four times daily and Tessalon perle (benzonatate), at a dose of 100 mg, orally, three times daily (tid) per need (prn) from the same day.   At the time of initial reporting, the outcome of the event upper respiratory infection was not resolved.  The event of upper respiratory infection was assessed as serious due to criterion of medical significance per company.  The reporter did not provide causality assessment to Flucelvax QIV.  Company Comment: The subject experienced upper respiratory tract infection 26 days after vaccination with the suspect product Flucelvax QIV. Reportedly, vaccination occurred during pregnancy at 19 weeks of gestation. Chronology is plausible. Patent's exposure to infective agents may provide more plausible alternative aetiology. Pregnant state and obesity (body mass index 32.2) may have contributed to development of the event. Vaccine exposure during pregnancy is assessed as not related per company's conventions. Considering all the above mentioned, causality between suspect product and the event upper respiratory tract infection is assessed as unlikely related.; Sender's Comments: The subject experienced upper respiratory tract infection 26 days after vaccination with the suspect product Flucelvax QIV. Reportedly, vaccination occurred during pregnancy at 19 weeks of gestation. Chronology is plausible. Patent's exposure to infective agents may provide more plausible alternative aetiology. Pregnant state and obesity (body mass index 32.2) may have contributed to development of the event. Vaccine exposure during pregnancy is assessed as not related per company's conventions. Considering all the above mentioned, causality between suspect product and the event upper respiratory tract infection is assessed as unlikely related.