Birth year may predict flu shot effectiveness, new study suggests

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Provision of signed and dated informed consent form 2. Stated willingness to comply with all study procedures and availability for all study visits 3. Aged 18 years and older 4. In good health based on self-reported medical conditions via an online survey Exclusion Criteria: 1. Known allergic reactions to components of the study vaccine 2. Known latex allergy 3. History of severe reactions following previous immunization with licensed or unlicensed influenza virus vaccines 4. History of GBS within 6 weeks of receipt of a previous influenza vaccine 5. Immunosuppression as a result of an underlying illness or treatment with immunosuppressive or cytotoxic drugs, or use of anticancer chemotherapy or radiation therapy within the preceding 36 months 6. Treatment with immunoglobulin or another blood product within the 3 months prior to enrollment in this study 7. Active neoplastic disease (excluding non-melanoma skin cancer or prostate cancer that is stable in the absence of therapy) or a history of any hematological malignancy ("active" is defined as having received treatment within the past 5 years) 8. Long-term (greater than 2 weeks) usage of oral or parenteral steroids, or high-dose inhaled steroids 9. Administration of an influenza vaccine within 2 months prior to enrollment 10. Known acute or chronic medical condition that, in the opinion of the investigator or appropriate sub-investigator, would render vaccination unsafe or would interfere with the evaluation of responses 11. Participation in a study that involves an experimental agent or having received an experimental agent (other than a COVID-19 vaccine) within 1 month prior to enrollment or expecting to receive another experimental agent during the study period 12. Intends to donate blood during the study period 13. Any condition that would, in the opinion of the site investigator, place the subject at an unacceptable risk of injury or render the subject unable to meet the requirements of the protocol 14. Pregnancy 15. Known human immunodeficiency virus, hepatitis B, or hepatitis C infection 16. Any condition that the principal investigator believes may interfere with successful completion of the study