Can your first flu shape how well the vaccine works?

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

Inclusion Criteria: 1. Aged equal to or greater than 9 years of age and weigh at least 50 pounds 2. The subject must be in good health, as determined by: medical history; and targeted physical examination, when necessary, based on medical history. Stable medical or psychiatric condition is defined as: no recent increase in prescription medication, dose, or frequency of medication in the last 3 months and health outcomes of the specific disease are considered to be within acceptable limits in the last 6 months 3. The subject is able to understand and comply with the planned study procedures, including being available for all study visits 4. The subject/parent has provided informed consent/assent prior to any study procedures 5. Subjects who have not received seasonal flu vaccine for the current year Exclusion Criteria: 1. Subject report of known hypersensitivity to allergy to components of the study vaccine or other components of the study vaccine 2. Subject report of known latex allergy 3. Subject report of a history of severe reactions following previous immunization with licensed or unlicensed influenza virus vaccines 4. Subject report of a history of Guillain-Barre syndrome within 6 weeks of receipt of a previous influenza vaccine 5. The subject is a female of childbearing potential who is currently pregnant or breastfeeding or intends to become pregnant during the study period between enrollment and 90 days following receipt of vaccine. Pregnancy will be determined by subject interview. Pregnancy testing is not done in this study since there is no increased risk in pregnancy 6. The subject is immunosuppressed 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 7. The subject has an 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. For this criterion, "active" is defined as having received treatment within the past 5 years 8. Have taken high-dose inhaled corticosteroids within 30 days prior to study vaccination. High-dose defined as per age as using inhaled high dose per reference chart https://www.nhlbi.nih.gov/health-pro/guidelines/current/asthma-guidelines/quick-reference-html#estimated-comparative-daily-doses 9. The subject received immunoglobulin or another blood product within the 3 months prior to enrollment in this study 10. The subject has received an inactivated vaccine within the 2 weeks or a live vaccine within the 4 weeks prior to enrollment in this study or plans to receive another vaccine within the next 28 days after vaccination 11. The subject has an 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. These conditions include any acute or chronic medical disease or conditions defined as persisting for 3 months (defined as 90 days) or longer, that would place the subject at an unacceptable risk of injury, render the subject unable to meet the requirements of the protocol, or may interfere with the evaluation of responses of the subject's successful completion of the study 12. Subjects with an active infection or that has an acute illness or an oral temperature greater than 99.9 degrees Fahrenheit (37.7 degrees Celsius) within 3 days prior to enrollment or vaccination. Subjects who had an acute illness that was treated symptoms resolved are eligible to enroll as long as treatment is completed and symptoms resolved \> 3 days prior to enrollment 13. The subject is currently participating or plans to participate in a study that involves an experimental agent (vaccine, drug, biologic, device, blood product, or medication) or has received an experimental agent within 1 month prior to enrollment in this study, or expects to receive another experimental agent during participation in this study, or intends to donate blood during the study period 14. The subject has 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 15. The subject has a history of alcohol or drug abuse in the 5 years prior to enrollment 16. The subject has a known human immunodeficiency virus, hepatitis B, or hepatitis C infection 17. Subject weighs less than 50 lbs 18. Subject expects to have a medical procedure during the upcoming 8 weeks that estimates blood loss to exceed 400 cc for adults or for children would exceed 3 ml/kg