Maternal and Fetal Outcomes Following Influenza Vaccination in Pregnancy

• Conditions: Pregnancy Related; Influenza Virus Vaccine Adverse Reaction
• Interventions: Biological: influenza vaccine

• Registration Number: NCT04579822
• Lead Sponsor: Sungkyunkwan University

Brief Summary

This is a nationwide cohort study to assess maternal and fetal outcomes following vaccination with a quadrivalent influenza vaccine (QIV) during pregnancy.

Detailed Description

The Korean National Immunization Program (NIP) first introduced quadrivalent influenza immunization for all pregnant women in the 2020-2021 season. This nationwide cohort study is proposed to assess the risks of adverse maternal and fetal outcomes following vaccination with a quadrivalent influenza vaccine (QIV) during pregnancy. We will use the national health insurance database from the National Health Insurance Service (NHIS) linked with the national immunization program registry data from the Korea Centers for Diseases Control \& Prevention (KCDC).

Study Timeline

• Study First Submitted: 2020-09-28
• Status Verified: 2020-10
• Study Start: 2020-10-01
• Study First Submitted QC: 2020-10-05
• Last Update Submitted: 2020-10-05
• Study First Posted: 2020-10-08
• Last Update Posted: 2020-10-08
• Primary Completion: 2021-10-31
• Study Completion: 2022-12-31

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: Female
• Target Recruitment: 300000

Inclusion Criteria

• Pregnant women between September 22, 2020, and April 30, 2021.

Exclusion Criteria

• Women aged <20 or >45 years
• Pregnancies with a chromosomal abnormality
• Pregnancies with exposure to a known teratogenic medication

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Pregnant women vaccinated with a QIV	influenza vaccine	Women aged 20-44 years who had received a QIV during their pregnancy between September 22, 2020, and April 30, 2021, under the national immunization program in South Korea.
Pregnant women unvaccinated with a QIV	influenza vaccine	Women aged 20-44 years who had not received a QIV during their pregnancy between September 22, 2020, and April 30, 2021, under the national immunization program in South Korea.

Primary Outcome Measures

Name	Time	Method
Risk of poor health outcomes in neonates	from delivery up to 1 year after birth	Respiratory distress, neonatal intensive care unit admission, and hospital visits with neonatal infection or fever, which are confirmed by diagnosis and healthcare utilization records in the NHIS database.
Risk of adverse pregnancy outcomes	from delivery up to 1 year after birth	Spontaneous abortion, stillbirth, neonatal death, congenital anomaly, pre-term birth, fetal growth restriction, small for gestational age, and low birth weight, which are confirmed by diagnostic records in the NHIS database.
Risk of vaccine-related adverse events	from delivery up to 1 year after birth	Vaccine-related adverse events confirmed by diagnostic records in the NHIS database.
Risk of poor health outcomes in pregnant women	from delivery up to 1 year after birth	Hospital admission, emergency department visits, influenza infection, and hospitalization with influenza infection, which are confirmed by diagnosis and healthcare utilization records in the NHIS database.

Secondary Outcome Measures

Name	Time	Method
Risk of pregnancy-related complications	from delivery up to 1 year after birth	Pre-eclampsia/eclampsia, gestational diabetes mellitus, antenatal bleeding, postpartum hemorrhage, and maternal death, which are confirmed by diagnostic records in the NHIS database.