Development of Childhood Anti-Influenza Immunity

Inclusion Criteria

• •1. Age:
• •* Between 6 and 12 months at the time of enrollment to participate in the vaccination arm of age cohort 1A
• •* Between 3 and 12 months at the time of enrollment to participate in the natural infection arm of age cohort 1B
• •* \> 12 months, birth date after 2009 for either the vaccination (A) or natural infection (B) arm of age cohort 2
• •* Birth date between 2006 and 2009 for either the vaccination (A) or natural infection (B) arm of age cohort 3
• •* Birth date between 2003 and 2006 for the vaccination (A) or natural infection (B) arm of age cohort 4
• •2. Gestational age of = / \> 37 weeks at birth
• •3. Parent/Legally Authorized Representative (LAR) can provide informed consent, with children = / \> 8 years of age providing informed assent
• •4. Available for the duration of the study
• •5. History of previous primary inactivated influenza vaccine (IIV) vaccination (at least 2 previous doses for age \< 9 yrs, at least 1 previous dose for age 9 and older) only for participation in the vaccination (A) arm of age cohorts 2, 3, or 4
• •6. Acute illness documented by rapid influenza test, polymerase chain reaction (PCR) testing, or testing done by either University of Rochester Medical Center (URMC) Labs or Rochester General Hospital (RGH) Clinical Microbiology Labs to be due to influenza virus only for participation in the natural infection arms (B) of age cohorts 1-4
• •7. Children enrolled in the cohort A (vaccination cohort) are required to have an appropriate weight and vital signs as determined by a licensed medical provider. Children enrolled in the cohort B (natural infection cohort) are required to have an appropriate weight and clinically stable vital signs as determined by a licensed medical provider\* \*Children will not qualify for study participation if their weight is more than 2.5 standard deviations below population norms. This will be determined through calculation of a Z score using the PediTools website (https://www.peditools.org/) utilizing the appropriate Centers for Disease Control and Prevention (CDC) growth calculators for age