Immune Responses in Health Care Personnel

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: Recruiting
• Conditions: Influenza
• Intervention / Treatment: Biological: influenza vaccine

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: Observational
• Enrollment (Estimated): 150

Contacts and Locations

• Study Contact: Name: Hanna Nohynek, MD, PhD; Phone Number: +358 29 524 8246; Email: hanna.nohynek@thl.fi
• Study Contact Backup: Name: Merit Melin, PhD; Phone Number: +358 29 524 8903; Email: merit.melin@thl.fi

Study Locations

• Finland
  • Helsinki, Finland
    • Recruiting
    • The Hospital District of Helsinki and Uusimaa
    • Contact: Veli-Jukka Anttila, MD, Docent; Phone Number: +358 50 4271512; Email: veli-jukka.anttila@hus.fi

Participation Criteria

Eligibility Criteria

• 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

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
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

Outcome Measure	Measure Description	Time Frame
Humoral immunity against each present season's vaccine and circulating influenza strains	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

Outcome Measure	Measure Description	Time Frame
Humoral immunity against previous seasons' vaccine and circulating influenza strains	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	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	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

Outcome Measure	Measure Description	Time Frame
Factors affecting humoral and/or cellular immune responses to influenza viruses or vaccination	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	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	developing laboratory methodologies to assess immunity to influenza and other microbes causing vaccine preventable diseases	10 years

Collaborators and Investigators

• Sponsor: Finnish Institute for Health and Welfare
• Collaborators: Hospital District of Helsinki and Uusimaa
• Investigators: Principal Investigator: Hanna Nohynek, MD, PhD, Finnish Institute for Health and Welfare

Study record dates

Study Major Dates

• Study Start (Actual): October 18, 2017
• Primary Completion (Estimated): October 14, 2027
• Study Completion (Estimated): October 14, 2027

Study Registration Dates

• First Submitted: October 13, 2017
• First Submitted That Met QC Criteria: October 23, 2017
• First Posted (Actual): October 26, 2017

Study Record Updates

• Last Update Posted (Actual): August 20, 2025
• Last Update Submitted That Met QC Criteria: August 18, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Keywords: influenza; vaccination; humoral immunity; immune responses; cellular immunity; health care workers
• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; Orthomyxoviridae Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Influenza, Human
• Other Study ID 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