Influenza Vaccine Effectiveness of a Quadrivalent Vaccine in Pregnant Women and Young Infants, 2019-2020

Completed

• Conditions: Influenza in Human

• Registration Number: NCT04723771
• Lead Sponsor: University of Athens

Brief Summary

Influenza is associated with an increased risk for serious illness, hospitalization and death in pregnant women and young infants. The investigators estimated the effectiveness of a quadrivalent inactivated influenza vaccine (QIV) in pregnant women and their infants in 2019-2020 influenza season. Women were activelly followed during the influenza season on a weekly basis through telephone call in order to collect data about the onset of fever and/or respiratory symptoms by them or their young infants. Polymerase chain reaction testing in pharyngeal samples was offered to pregnant women and infants with influenza-like illness (ILI). A total of 636 pregnant women and 474 infants were studied. A Bayesian beta-binomial model was used.

Detailed Description

Study period: Influenza 2019-2020 season

The investigators followed actively the pregnant women and their infants in order to collect prospectively data on a weekly basis through phone calls during the entire influenza season.

Definitions:

* ILI was defined as the sudden onset of symptoms and fever, malaise, myalgia or headache, and cough, sore throat or shortness of breath.

* ARI was defined as the presence of at least one respiratory symptom, regardless of fever.

* Febrile episode was defined as the presence of fever only.

* Fever was defined as a temperature of 38.0 C in at least two measurements within 24h.

* The diagnoses of pneumonia and AOM were accepted as reported by the physicians who provided care to the women or their infants.

The 2019-2020 QIV Vaxigrip-Tetra was used to vaccinate pregnant women.

Study Timeline

• Study Start: 2019-09-01
• Primary Completion: 2020-04-30
• Study Completion: 2020-08-31
• Study First Submitted: 2020-09-22
• Study First Submitted QC: 2021-01-20
• Study First Posted: 2021-01-26
• Status Verified: 2021-05
• Last Update Submitted: 2021-05-06
• Last Update Posted: 2021-05-11

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Female
• Target Recruitment: 949

Inclusion Criteria

Pregnant women >18 years old and <45 years old, cared at Alexandra General Hospital (Athens, Greece) between October 16 and January 27, 2020

Exclusion Criteria

• <18 years old or >45 years old
• not in stable health
• already vaccinated against influenza
• history of Guillain-Barré syndrome
• history of hypersensitivity to influenza vaccines
• immunosuppression
• history of investigational drug <30 days
• history of immunoglobulins or blood products <3 months
• fever at day of interview (enrollment day)

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
rates of laboratory-confirmed influenza in vaccinated and unvaccinated pregnant women	2019-2020 influenza season	influenza vaccine effectiveness against laboratory-confirmed influenza in pregnant women
rates of laboratory-confirmed influenza in young infants whose mothers were vaccinated and in infants of unvaccinated mothers	2019-2020 influenza season	influenza vaccine effectiveness against laboratory-corfirmed influenza in young infants

Secondary Outcome Measures

Name	Time	Method
rates of acute respiratory infection, influenza-like illness, febrile episode, use of antibiotics, use of antivirals, pneumonia, acute otitis media (for infants only), healthcare seeking and hospitalization in pregnant women and their infants	2019-2020 influenza season	influenza vaccine effectiveness against the abovementioned secondary outcomes

Trial Locations

Locations (1)

First Department of Obstetrics and Gynecology, University of Athens; 🇬🇷 Athens, Attica, Greece