Immune Responses in Health Care Personnel

August 18, 2025 updated by: Finnish Institute for Health and Welfare

Immune Responses to Influenza Vaccinations and Viruses Among Health Care Personnel

This is an investigator-initiated 10 year long open cohort observational study, aiming to increase the understanding of the humoral and cellular immunological mechanisms of vaccination against influenza, including effects of repeated vaccination, the duration of protection, immunity against circulating viruses, as well as factors affecting the immunological responses and immunity against other vaccine preventable infectious diseases among health care personnel.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Influenza vaccination is given according to the normal routine of Hospital District of Helsinki and Uusimaa (HUS) occupational health care. Blood samples will be collected before vaccination, 5 weeks after vaccination and 6 months after vaccination. Both the same participants and also new participants will be recruited each year. The analysis will be mainly descriptive.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
150

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Finland
      • Helsinki, Finland
        • Recruiting
        • The Hospital District of Helsinki and Uusimaa
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 64 years (Adult)

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Health care professionals affiliated by HUS

Description

Inclusion Criteria:

  • Members of health care or laboratory personnel in HUS having decided to take the seasonal influenza vaccination by the routine occupational health care service
  • General good health as established by or volunteer's own statement
  • Written informed consent
  • Presumably able and willing to participate in the study during the starting influenza season

Exclusion Criteria:

  • Any confirmed or suspected immunosuppressive or immunodeficient condition, including human immunodeficiency virus (HIV) infection.
  • Administration (longer than 14 days) of immunosuppressants or other immune- modifying drugs within 6 months before the vaccination; oral corticosteroids in dosages of 20 mg/day or more prednisolone or equivalent are excluded; inhaled or topical steroids are allowed.
  • Pregnancy or lactation
  • Acute disease at the time of enrolment (defined as the presence of a moderate or severe illness with or without fever)
  • Contraindication for influenza vaccination
  • Any other criteria which, in the investigator's or dedicated study staff member's opinion, would compromise the ability of a subject to participate in the study, a subject's well-being, or the outcome of the study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Influenza vaccine recipients
Health care workers vaccinated by their occupational health care according to the routine praxis.
Biological: influenza vaccine
Vaccine for prevention of influenza. Vaccines change by influenza season.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Humoral immunity against each present season's vaccine and circulating influenza strains
Time Frame: 10 years
The presence and titer of antibodies against circulating influenza virus strains and vaccine strains of the current season from pre- and post-vaccination serum samples
10 years

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Humoral immunity against previous seasons' vaccine and circulating influenza strains
Time Frame: 10 years
To assess the presence and titer of antibodies to circulating influenza strains and vaccine virus strains of previous seasons from pre- and post-vaccination serum samples
10 years
Cellular immunity against current and previous seasons' vaccine and circulating influenza strains
Time Frame: 10 years
The cellular immune responses to circulating influenza viruses and vaccine strains of the current and previous seasons from pre- and post-vaccination peripheral blood mononuclear cells (PBMCs) and cell culture supernatants
10 years
Effect of repeated vaccination against influenza
Time Frame: 10 years
The effect of the number of previous influenza vaccinations on the quality and quantity of Humoral and cellular immunity to circulating influenza strains and vaccine strains of the current and previous seasons
10 years

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Factors affecting humoral and/or cellular immune responses to influenza viruses or vaccination
Time Frame: 10 years
Exploration of biological or chemical factors that are/will be known or suspected to affect the humoral and/or cellular immune responses to influenza viruses or vaccination
10 years
Immunity against other microbes causing vaccine preventable diseases among health care workers
Time Frame: 10 years
Assessment of humoral and cellular immunity to microbes other than influenza virus causing vaccine preventable diseases
10 years
Developing methods to measure immunity against vaccine preventable diseases
Time Frame: 10 years
developing laboratory methodologies to assess immunity to influenza and other microbes causing vaccine preventable diseases
10 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Finnish Institute for Health and Welfare

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Hospital District of Helsinki and Uusimaa

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Hanna Nohynek, MD, PhD, Finnish Institute for Health and Welfare

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 18, 2017

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
October 14, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
October 14, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 13, 2017

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 23, 2017

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 26, 2017

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 20, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 18, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • FinFLU_HCPimmu_2017THL

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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