An observational study in Influenza, sponsored by Finnish Institute for Health and Welfare. Recruiting at 1 site in Finland. Open to participants aged 18 Years to 64 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-08-20.
Sponsored by Finnish Institute for Health and Welfare · Observational
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.
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.
2,356 studies on the registry are indexed under Influenza, Human; 184 are open to participants now.
This study's planned enrollment of 150 is below the median of 388 across 332 observational studies indexed under Influenza, Human.
Browse Influenza, Human studies →Finnish Institute for Health and Welfare is the lead sponsor of 42 studies on the registry; 3 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Health care professionals affiliated by HUS
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
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
Time frame: 10 years
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
Time frame: 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
Time frame: 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
Time frame: 10 years
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
Time frame: 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
Time frame: 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
Time frame: 10 years
Plan to share: No
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Finnish Institute for Health and Welfare