Simultaneous mRNA COVID-19 and IIV Vaccination in Pregnancy Study

Inclusion Criteria:

• Pregnant people ages 18 years or older at enrollment

• Gestational age < 34 weeks 0 days based on reconciliation of last menstrual periodand ultrasound dating. Estimated due date (EDD) and Gestational Age (GA-EDD) will bebased on reconciliation of "sure" first day of the last menstrual period (LMP) andearliest dating ultrasound. If the LMP is uncertain, then the earliest datingultrasound will be used to determine EDD and GA. If the ultrasound derived-EDD is inagreement with sure-LMP derived EDD, then the LMP-derived EDD is used to determineGA. If the ultrasound derived EDD is not in agreement with the LMP-derived EDD, theultrasound-derived EDD is used to determine GA.

• Intention to receive mRNA COVID-19 vaccine

• Intention to receive influenza vaccine

• Willing to provide written informed consent

• Intention of being available for entire study period and complete all relevant studyprocedures, including follow-up phone calls and collection of delivery information.

• Ability to speak English, Spanish or Haitian/Creole depending on site*

• Duke will enroll English and Spanish speaking individuals.

• Boston will enroll English, Spanish and Haitian Creole speaking individuals.

• CCHMC will enroll English speaking individuals.

• Emory will enroll English speaking individuals.

• Wake Forest will enroll English and Spanish speaking individuals.

• Receiving or planning to receive prenatal care.

Exclusion Criteria:

• Has immunosuppression because of an underlying illness or medications, such asantirejection/transplant regimens or immunomodulatory agents. Stable HIV disease ispermitted per the following parameters: a. Confirmed stable HIV disease defined as documented viral load <50 copies/mL andCD4 count >200 within 6 months before enrollment, and on stable antiretroviraltherapy for at least 6 months

• Has known hepatitis B (HBV) or hepatitis C (HCV). Stable HBV or HCV are permittedper the following parameters:

1. If known HBV: confirmed inactive chronic HBV infection: HBsAg present for ≥6months and HBeAg negative, anti-HBe positive; serum HBV DNA <2000 IU/mL;persistently normal ALT or AST levels; in those who had liver biopsy, findingsthat confirm absence of significant necroinflammation

2. If known HCV: evidence of sustained virological response for ≥12 weeks aftertreatment or without evidence of HCV RNA viremia (undetectable HCV RNA)

• Received oral, intramuscular or intravenous systemic immunosuppressants, orimmune-modifying drugs for >14 days in total within 6 months prior to any studyvaccine dose (for corticosteroids ≥ 20 mg/day of prednisone equivalent). Note:Topical medications are allowed.

• Has an active neoplastic disease (excluding nonmelanoma skin cancer), includingthose who used anticancer chemotherapy or radiation therapy during the currentpregnancy or recently (within 36 months of enrollment into study.)

• Signs or symptoms of active preterm labor, defined as regular uterine contractionswith cervical change (dilation/effacement)

• Known multi-fetal gestation

• Known fetal congenital anomaly, e.g., genetic abnormality or major congenitalmalformation based on antenatal ultrasound

• Intending to deliver at a site un-affiliated with the study team

• Prior receipt of influenza vaccine during the respective influenza season in whichthey are being enrolled

• Prior receipt of COVID-19 vaccine during the respective influenza season in whichthey are being enrolled

• Receipt of any licensed non-live vaccine within 7 days prior to study vaccination orintention of receiving any vaccines during the 7-day post-vaccination periods

• Receipt of any live vaccine during the current pregnancy

• Severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine,including egg protein, or after previous dose of any influenza vaccine

• History of a severe allergic reaction (e.g., anaphylaxis) after a previous dose orto a component of the mRNA COVID-19 vaccine

• History of Guillain-Barré syndrome within 6 weeks of a prior dose of any influenzavaccine.

• History of a diagnosed non-severe allergy to a component of the mRNA COVID-19vaccine

• History of a non-severe, immediate (onset less than 4 hours) allergic reaction afteradministration of a previous dose of mRNA COVID-19 vaccine

• History of multisystem inflammatory syndrome in children (MIS-C) or multisysteminflammatory syndrome in adults (MIS-A)

• History of myocarditis or pericarditis within 3 weeks after a dose of any COVID-19vaccine

• Documented COVID-19 infection within 6 weeks prior to enrollment confirmed by eithermedical history or lab testing

• Individuals who are known to be delivering early (<37 weeks)

• Receipt of blood or plasma products or immunoglobulin from 3 months before studyvaccine administration, or planned receipt through delivery, with an exception ofRho(D) immune globulin.

• Anyone who is a first-degree relative of any research study personnel or is anemployee supervised by study staff.

• Prior enrollment in the study

• Anyone who is already enrolled or plans to enroll in another clinical trial with aninvestigational product during the study period.*

*Per protocol, co-enrollment in observational or behavioral intervention studies ispermitted at any time. An investigational product may be permitted for therapy of anillness condition that occurs during the study period.

• Bleeding disorder or condition associated with prolonged bleeding that would presentas a safety risk per opinion of the investigator

• Any condition which, in the opinion of the investigators, may pose a health risk tothe subject or interfere with the evaluation of the study objectives.

Temporary Delay Criteria at Visit 1 and 2

• History of febrile illness (> 100.4°F or 38°C) within the past 72 hours prior tovaccine administration

• Any condition which, in the opinion of the investigators, may pose a temporaryhealth risk to the subject or interfere with the evaluation of the study objectives.

Visit 2 Eligibility Criteria Review

• History of Guillain-Barré syndrome within 6 weeks of a prior dose of any influenzavaccine.

• Prior receipt of influenza vaccine during the respective influenza season in whichthey are being enrolled

• Severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine,including egg protein, or after previous dose of any influenza vaccine

• Any condition which, in the opinion of the investigators, may pose a health risk tothe subject or interfere with the evaluation of the study objectives.