Immune Responses in Health Care Personnel

Study Overview
=================
Brief Summary
-----------------
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.

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.

Official Title
-----------------
Immune Responses to Influenza Vaccinations and Viruses Among Health Care Personnel

Conditions
-----------------
Influenza

Intervention / Treatment
-----------------
* Biological: influenza vaccine


Participation Criteria
=================
Eligibility Criteria
-----------------
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

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 64 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Influenza vaccine recipients<br>Health care workers vaccinated by their occupational health care according to the routine praxis. | Biological: influenza vaccine<br>* Vaccine for prevention of influenza. Vaccines change by influenza season.<br>|

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 | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
influenza, vaccination, health care workers, immune responses, humoral immunity, cellular immunity