Immunologic Response to FluMist vs. Flucelvax

Immunological Response to Influenza Vaccination in Children, Adolescents, and Young Adults: A RCT of FluMist vs. Flucelvax

The purpose of this study is to evaluate immunologic response to different types of influenza vaccine among children/adolescents/young adults 4-21 years of age. This is a randomized controlled trial (RCT), that will assess immune response in about 440 participants (about 220 per vaccine arm) pre- and post-vaccination to FluMist (live attenuated influenza vaccine given by nasal administration) and Flucelvax (egg-free cell-culture inactivated influenza vaccine).

This is a non-blinded, randomized controlled trial analyzing influenza vaccine immunogenicity response in children/adolescents/young adults aged 4-21 years given one of two FDA approved and licensed influenza vaccines: FluMist (live attenuated influenza vaccine by nasal administration) and Flucelvax (egg-free cell-culture inactivated influenza vaccine). This study will enroll about 440 healthy participants, about 220 per vaccine arm. Participants will be randomized in blocks of 4 using a 1:1 allocation to receive either FluMist or Flucelvax. Blood work will be conducted on all participants at baseline prior to vaccine receipt and post-vaccination at Day 7 (range 6-9 days) and Day 28 (range 21-35 days). The primary objective of the study is to determine pre- and post-serologic responses to each vaccine type.

Participants receiving live attenuated FluMist influenza vaccine will receive 0.2 mL given intranasally

Participants receiving inactivated Flucelvax influenza vaccine will receive 0.5 mL given intramuscularly

Participants randomized to this study influenza vaccine arm will receive FluMist live attenuated influenza vaccine at baseline after the baseline blood draw is complete.

Participants randomized to this study influenza vaccine arm will receive Flucelvax cell-culture inactivated influenza vaccine at baseline after the baseline blood draw is complete.

Rows in data tables represent different influenza antigens measured in 2019. Hemagglutination inhibition (HI) assay was conducted to assess immunologic outcome. Seroconversion is defined as a 4-fold or higher rise in HI titer post-vaccination given a pre-vaccination HI titer of >=10 and a final HI titer of >=40.

Rows in data tables represent different influenza antigens measured in 2020. Hemagglutination inhibition (HI) assay was conducted to assess immunologic outcome. Seroconversion is defined as a 4-fold or higher rise in HI titer post-vaccination given a pre-vaccination HI titer of >=10 and a final HI titer of >=40.

Rows in data tables represent different influenza antigens measured in 2019. Hemagglutination inhibition (HI) assay was conducted to assess immunologic outcome. Seroprotection is defined as a HI titer >= 1:110 at either time point.

Rows in data tables represent different influenza antigens measured in 2019. Hemagglutination inhibition assay was conducted to assess immunologic outcome. GMTs is defined as the anti-log of the mean of the log2 HI titers

Rows in data tables represent different influenza antigens measured in 2020. Hemagglutination inhibition (HI) assay was conducted to assess immunologic outcome. Seroprotection is defined as a HI titer >= 1:110 at either time point.

Rows in data tables represent different influenza antigens measured in 2020. Hemagglutination inhibition assay will be conducted to assess immunologic outcome. GMTs is defined as the anti-log of the mean of the log2 HI titers

Inclusion Criteria: aged 4-21 years; has prior vaccination history available (which can be determined based either on medical record review or through state registry review); plans to receive the current seasonal influenza vaccination at one of the recruiting sites Exclusion Criteria: unable or unwilling to completed required study activities, including informed consent, randomization to vaccine, and bloodwork; has already received influenza vaccine for the current season; has a known immunocompromising condition or is on an immunosuppressing medication (e.g., high dose steroids >10 days); is known to be pregnant; has a history of severe allergy to eggs or to influenza vaccine or any of its components

Individual participant data that underlie the results reported in the primary article, after deidentification, will be placed at the site mentioned below.

Researchers who provide a methodologically sound proposal and have appropriate data security and privacy plans in place