This is a prospective, single-arm study designed to understand the mechanisms that lead to a loss of response to influenza vaccine in older adults. The investigators will recruit and longitudinally follow a cohort of 75 older adults (65 years and older) who will receive three different influenza vaccines over three annual influenza seasons. Blood samples will be collected from the participants at sixteen study visits over three years. Nasal swab and stool samples will also be collected from participants at seven time-points across the study period. After completion of study visits other than the End of Study visit around vaccination in Year 3, participants will be offered the opportunity to be vaccinated with a different FDA approved influenza vaccine and participate in study visits for Year 4. The study is not designed to assess safety or tolerability of the influenza vaccines administered as part of this study.
This prospective, single-arm study is designed to understand the mechanisms that lead to a loss of response to influenza vaccine in older adults through the establishment of the FluVax3 cohort of healthy older adults. In this study, the investigators will perform comprehensive profiling of blood antibodies and immune cells over time, and associate specific age-related immune alterations with vaccine responder or non-responder status. This will allow the investigators to pinpoint biological pathways that can be targeted to enhance vaccine efficacy and that can also help the investigators progress towards developing a universal influenza vaccine. The results are expected to provide the foundation for new approaches to improve overall vaccine efficacy and protection in older adults, an outcome of significant public health relevance considering the vulnerability of this population. In this study, up to seventy-five (75) healthy adults aged 65 years and older who have not received influenza vaccination for the approaching influenza season will be enrolled in the study and vaccinated with influenza vaccines approved by the U.S Food and Drug Administration (FDA) and recommended by the Centers for Disease Control and Prevention (CDC) for individuals ≥65 years. All participants receive influenza vaccine during the 2022-23, 2023-24, and 2024-25 influenza seasons. Participants will receive Fluzone® Quadrivalent High-Dose vaccine during the 2022-23 flu season, FLUAD® Quadrivalent during the 2023-24 flu season and Flublok Quadrivalent in the 2024-2025 flu season. The study sample will be drawn from the population of healthy older participants in the catchment area of UConn Health in Farmington, CT. Study participation will involve six study visits around the flu vaccine each year and one final study visit for a total of nineteen study visits over three years. Blood samples will be collected at sixteen study visits for transcriptional, epigenetic and biological analyses pre- and post-vaccination. Nasal swab and stool samples will also be collected from participants at seven time-points across the study period. These microbiome samples will be stored and used in future research. After completion of study visits other than the End of Study visit around vaccination in Year 3, participants will be offered the opportunity to be vaccinated with the FDA approved Fluzone High Dose (trivalent) vaccine during the 2025-26 flu season and participate in study visits for Year 4. Blood samples will be collected from participants at an additional 5 timepoints and nasal swabs at an additional 2 timepoints across Year 4. The study is not designed to assess safety or tolerability of the influenza vaccines administered as part of this proposed study. This project will yield an unparalleled dataset from healthy older adults that will be used to identify fundamental mechanisms, cell populations, and pathways associated with durable protective antibody immune responses, and lack thereof, upon influenza vaccination. In sum, this study will reveal the mechanistic alterations that explain the heterogeneity in response to vaccines observed in older individuals. Understanding this heterogeneity opens the possibility of stratifying older adults for personalized vaccines. In addition, understanding the mechanistic overlap between the correlates of responsiveness to four different influenza vaccines will advance the ultimate development of a universal influenza vaccine, which is a key focus of NIAID's influenza research program. Finally, this study will generate a considerable amount of transcriptional and functional data related to the outputs of key innate immune and T/B-cell subsets involved in responses to influenza vaccines in older adults. These data will collectively become an important resource for future studies focused on the older adult immune system in health and disease.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
75
Participants will receive Fluzone® Quadrivalent High-Dose in the 2022-2023 flu season.
Participants will receive FLUAD® Quadrivalent in the 2023-2024 flu season.
Participants will receive Flublok Quadrivalent in the 2024-2025 flu season.
Participants will receive Fluzone® High-Dose Trivalent in the 2025-2026 flu season.
UConn Health, Center On Aging
Farmington, Connecticut, United States
Change in Antibody Responses to Influenza Vaccine Year One
In year one, healthy older participants will receive Fluzone Quadrivalent HD vaccine. Longitudinal blood samples will be collected and influenza-specific antibody responses will be assessed. Change in antibody response will be measured using Hemagglutination Inhibition (HAI) from baseline to day 35 and day 180.
Time frame: Baseline, Day 35, Day 180
Change in Antibody Responses to Influenza Vaccine Year Two
In year two, healthy older participants will receive FLUAD vaccine. Longitudinal blood samples will be collected and influenza-specific antibody responses will be assessed. Change in antibody response will be measured using Hemagglutination Inhibition (HAI) from baseline to day 35 and day 180.
Time frame: Baseline, Day 35, Day 180
Change in Antibody Responses to Influenza Vaccine Year Three
In year three, healthy older participants will receive Flublok Quadrivalent vaccine. Longitudinal blood samples will be collected and influenza-specific antibody responses will be assessed. Change in antibody response will be measured using Hemagglutination Inhibition (HAI) from baseline to day 35 and day 180.
Time frame: Baseline, Day 35, Day 180
Change in Antibody Responses to Influenza Vaccine Year Four
In year four, healthy older participants will receive Fluzone® High-Dose Trivalent vaccine. Longitudinal blood samples will be collected and influenza-specific antibody responses will be assessed. Change in antibody response will be measured using Hemagglutination Inhibition (HAI) from baseline to day 35 and day 180.
Time frame: Baseline, Day 35, Day 180
Evaluate changes in functional status of immune cells in response to Influenza Vaccine in Year One
Evaluate changes in functional status of immune cells in older participants following administration of Fluzone Quadrivalent HD vaccine. A longitudinal analysis of different cell populations (B Cells, Functional T/B Cells, and monoclonal antibodies) in whole blood samples will be analyzed at baseline and 35 days post vaccination using single cell assays and ELISA.
Time frame: Baseline, Day 7, Day 35
Evaluate changes in functional status of immune cells in response to Influenza Vaccine in Year Two
Evaluate changes in functional status of immune cells in older participants following administration of FLUAD vaccine. A longitudinal analysis of different cell populations (B Cells, Functional T/B Cells, and monoclonal antibodies) in whole blood samples will be analyzed at baseline and 35 days post vaccination using single cell assays and ELISA.
Time frame: Baseline, Day 7, Day 35
Evaluate changes in functional status of immune cells in response to Influenza Vaccine in Year Three
Evaluate changes in functional status of immune cells in older participants following administration of Flublok Quadrivalent vaccine. A longitudinal analysis of different cell populations (B Cells, Functional T/B Cells, and monoclonal antibodies) in whole blood samples will be analyzed at baseline and 35 days post vaccination using single cell assays and ELISA.
Time frame: Baseline, Day 7, Day 35
Evaluate changes in functional status of immune cells in response to Influenza Vaccine in Year Four
Evaluate changes in functional status of immune cells in older participants following administration of Fluzone High Dose Trivalent vaccine. A longitudinal analysis of different cell populations (B Cells, Functional T/B Cells, and monoclonal antibodies) in whole blood samples will be analyzed at baseline and 35 days post vaccination using single cell assays and ELISA.
Time frame: Baseline, Day 7, Day 35
Number of genes upregulated in response to Influenza Vaccine in Year One
RNA-seq and scRNA-seq will be used to assess the number of genes upregulated in response to Fluzone Quadrivalent HD vaccination.
Time frame: Baseline, Day1, Day 7
Number of genes upregulated in response to Influenza Vaccine in Year Two
RNA-seq and scRNA-seq will be used to assess the number of genes upregulated in response to FLUAD vaccination.
Time frame: Baseline, Day 1, Day 7
Number of genes upregulated in response to Influenza Vaccine in Year Three
RNA-seq and scRNA-seq will be used to assess the number of genes upregulated in response to Flublok Quadrivalent vaccination.
Time frame: Baseline, Day1, Day 7
Number of genes upregulated in response to Influenza Vaccine in Year Four
RNA-seq and scRNA-seq will be used to assess the number of genes upregulated in response to Fluzone High Dose Trivalent vaccination.
Time frame: Baseline, Day1, Day 7
Number of chromatin accessibility regions activated in response to Influenza Vaccine in Year One
snATAC-seq will be used to assess the number of open chromatin regions activated in response to Fluzone Quadrivalent HD vaccination.
Time frame: Baseline, Day1, Day 7
Number of chromatin accessibility regions activated in response to Influenza Vaccine in Year Two
snATAC-seq will be used to assess the number of open chromatin regions activated in response to FLUAD vaccination.
Time frame: Baseline, Day1, Day 7
Number of chromatin accessibility regions activated in response to Influenza Vaccine in Year Three
snATAC-seq will be used to assess the number of open chromatin regions activated in response to Flublok Quadrivalent influenza vaccination.
Time frame: Baseline, Day1, Day 7
Number of chromatin accessibility regions activated in response to Influenza Vaccine in Year Four
snATAC-seq will be used to assess the number of open chromatin regions activated in response to Fluzone High Dose Trivalent vaccination.
Time frame: Baseline, Day1, Day 7
Changes in number of cDCs, Tfh, Th10, and B lymphocytes in response to Influenza Vaccine in Year One
Flow cytometry will be used to assess cell compositional changes in PBMCs and immune cell subsets (cDCs, Tfh, Th10, and B lymphocytes) in response to Fluzone Quadrivalent HD vaccination.
Time frame: Baseline, Day1, Day 7, Day 35, Day 180
Changes in number of cDCs, Tfh, Th10, and B lymphocytes in response to Influenza Vaccine in Year Two
Flow cytometry will be used to assess cell compositional changes in PBMCs and immune cell subsets (cDCs, Tfh, Th10, and B lymphocytes) in response to FLUAD vaccination.
Time frame: Baseline, Day1, Day 7, Day 35, Day 180
Changes in number of cDCs, Tfh, Th10, and B lymphocytes in response to Influenza Vaccine in Year Three
Flow cytometry will be used to assess cell compositional changes in PBMCs and immune cell subsets (cDCs, Tfh, Th10, and B lymphocytes) in response to Flublok Quadrivalent influenza vaccination.
Time frame: Baseline, Day1, Day 7, Day 35, Day 180
Changes in number of cDCs, Tfh, Th10, and B lymphocytes in response to Influenza Vaccine in Year Four
Flow cytometry will be used to assess cell compositional changes in PBMCs and immune cell subsets (cDCs, Tfh, Th10, and B lymphocytes) in response to Fluzone High Dose Trivalent influenza vaccination.
Time frame: Baseline, Day1, Day 7, Day 35, Day 180
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