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NCT Number: NCT02198638

Effect of Influenza Vaccination of Healthcare Workers (HCW) on the Risk of Influenza in Patients Hospitalized in Short Stays Units

Hospital acquired influenza is associated with significant morbidity and mortality in hospitalized patients notably elderly patients. Vaccination of HCW is recommended to prevent influenza transmission in healthcare setting.

Outbreaks of hospital acquired influenza were reported in stays with high vaccine coverage in patients (higher than 85%). It is necessary to underline that an adequate vaccine cover in the elderly population will not necessarily result in a total control of the incidence. Consequently, the prevention of influenza outbreaks in this vulnerable population must also include the reduction of the exposure to the influenza viruses, in particular thanks to the vaccination of HCW.

A pilote case-control study, implemented in Edouard Herriot hospital (at Lyon University hospitals), indicates that a shielding effect of more than 35% of vaccinated HCW on hospital acquired influenza among patients (Bénet et al.; BMC Infectious Diseases 2012). The results suggest a protective effect but investigations, carried out on a more important sample are needed to validate the benefit of HCW vaccination.

The aim of this prospective multicentric cohort study is to estimate incidence of influenza among hospitalized patients according to % of influenza vaccination of HCW in short stay units.

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Key information

Conditions

Patient With Influenza Like Illness Cross Infection Disease Attributes Iatrogenic Disease Infections Influenza, Human Orthomyxoviridae Infections Pathologic Processes Pathological Conditions, Signs and Symptoms RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Hospices Civils de Lyon - Hôpital Edouard Herriot, Lyon, France

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Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • All adults patients and healthcare workers of the participating units
  • With Influenza Like Illness

Exclusion criteria

  • Patients aged < 18 years

Treatment and study plan

A nasal swab

Biological

A nasal swab was performed by a research assistant and influenza virus infection was confirmed by enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction on viral cultures

Primary outcomes

  1. Incidence of influenza among hospitalized patients according to % of influenza vaccination of HCW in short stay units

    Time frame: After 16 months (2 influenza seasons: from 15 December 2013 to 15 April 2014 and from 15 December 2014 to 15 April 2015)

    Study participation was proposed to each patient who presented ILI (influenza like illness) at admission or during hospitalization. ILI was defined as fever >37.8°C or cough or sore throat. Vaccination against influenza during the ILI season was collected by oral interview. After the interview, a nasal swab was performed by a research assistant and influenza virus infection was confirmed by enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction on viral cultures.

Secondary outcomes

  1. Estimation of influenza vaccine failure according to serotyping of viral strains

    Time frame: After 16 months (2 influenza seasons: from 15 December 2013 to 15 April 2014 and from 15 December 2014 to 15 April 2015)

    strains of confirmed influenza virus were analysed by reverse transcription-polymerase chain reaction on viral cultures.

  2. Does incidence of community influenza influence hospital acquired influenza infections

    Time frame: After 16 months (2 influenza seasons: from 15 December 2013 to 15 April 2014 and from 15 December 2014 to 15 April 2015)

    comparison of results observed during the 2 seasons

Sponsors and collaborators

Lead sponsor

Hospices Civils de Lyon

Other

Registry information

Official study title

Influenza Vaccination of HCW and Hospital Acquired Influenza in Patients

Important dates

Study start
2013
Primary completion
2015
Study completion
2015
First posted
Jul 23, 2014
Registry last updated
Aug 11, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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