The goal of this study is to understand the impact on the human immune system's response to the four strain flu vaccine in individuals who have "imprinted" on specific influenza strains. It will also consider the effects of repeated prior annual influenza vaccination on the immune system.
Seasonal influenza outbreaks continue to cause substantial disease burden, with an estimated 3-5 million cases of severe illness, and 250,000 to 500,000 deaths worldwide each year. In the United States, the Centers for Disease Control and Prevention (CDC) reports that influenza has resulted in 9.2-35.6 million illnesses with 12,000-56,000 deaths annually since 2010. There is an urgent need to better understand the immunologic responses to current licensed vaccines in order to develop a more effective vaccine that does not rely on annual updates, provides broad protection, and is durable; i.e., a universal influenza vaccine. The immune response to the influenza vaccine is affected by many parameters, including prior imprinting to a specific influenza strain based on birth cohort, as well as prior influenza vaccination. The FDA-approved, quadrivalent seasonal influenza vaccine that will be administered contains four distinct strains, two influenza A viruses (IAVs) and two influenza B viruses (IBVs). The approved seasonal influenza vaccine will be given for each season of influenza: 2018-2019, 2019-2020, and 2020-2021. This study is a prospective pilot study conducted over the course of three years (with three specific influenza seasons studied). For each year (2018-2019, 2019-2020, and 2020-2021), two cohorts of 10 participants each, who are in good health and meet all eligibility criteria, will be recruited. The influenza A virus subtype H3N2 cohort (N=30 total, 10 per year) will consist of participants born between 1968-1977, and the influenza A virus subtype H1N1 cohort (N=30 total, 10 per year) will consist of participants born between 1948-1957. Each participant will make a total of six visits to the Hope Clinic. Day 1 will include the informed consent process, and screening to ensure the subject meets all inclusion criteria and meets no exclusion criteria. For the consenting and eligible subject, the visit will also include pre-vaccination phlebotomy for baseline immunogenicity laboratory assays. After baseline sample collection, the participants will receive the FDA-approved seasonal influenza vaccine. Subsequent study visits up to 180 days post-vaccination will include collection for immunogenicity assays. This study is not powered to test a formal null hypothesis. Rather, it is a hypothesis-generating investigation that will hopefully lead to larger trials based on the findings. The study will be conducted over the course of three years to increase the total sample population size and to validate the findings over different influenza seasons.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
39
The FDA-approved, quadrivalent seasonal influenza vaccine that will be administered contains four distinct strains, two influenza A viruses and two influenza B viruses.
The Hope Clinic of the Emory Vaccine Center
Atlanta, Georgia, United States
The Number of Participants Achieving Seroprotection Against Each Strain
Seroprotection against each strain contained in the seasonal quadrivalent influenza vaccine (A/H1N1, A/H3N2, B/Phuket, and B/Colorado) were measured by hemagglutination inhibition (HAI) antibody response. Seroprotection is defined as a titer of ≥ 40.
Time frame: 28 days after vaccination
The Number of Participants Achieving Seroconversion Against Each Strain
Seroconversion against each strain contained in the seasonal quadrivalent influenza vaccine was measured by HAI antibody response. Seroconversion is defined as a four-fold rise in HAI post- compared to pre-vaccination, or a titer of ≥40 if the pre-vaccination titer was \<10.
Time frame: 28 days after vaccination
Geometric Mean Titers (GMTs) of Serum HAI Against Each Strain
The geometric scale is logarithmic. A geometric mean is calculated by averaging the logarithms of the test values and then converting the mean to a real number.
Time frame: 28 days after vaccination
The Proportion of Participants Achieving Seroprotection or Seroconversion Against Each Strain Measured by Neutralizing Antibody (NAb) Response
Seroprotection/seroconversion against each strain contained in the seasonal quadrivalent influenza vaccine will be measured by neutralizing antibody (NAb) response. The proportion of subjects achieving seroprotection (titer of ≥ 40) or seroconversion (four-fold rise in NAb post- compared to pre-vaccination, or a titer of ≥40 if the pre-vaccination titer was \<10) against each strain will be assessed.
Time frame: 28 days after vaccination
Geometric Mean Titers (GMTs) of Serum NAb Against Each Strain
The geometric scale is logarithmic. A geometric mean is calculated by averaging the logarithms of the test values and then converting the mean to a real number.
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Time frame: 28 days after vaccination
The Number of Participants Achieving Seroprotection Against Each Strain
Seroprotection against each strain contained in the seasonal quadrivalent influenza vaccine (A/H1N1, A/H3N2, B/Phuket, and B/Colorado) were measured by hemagglutination inhibition (HAI) antibody response. Seroprotection is defined as a titer of ≥ 40.
Time frame: 180 days after vaccination
The Number of Participants Achieving Seroconversion Against Each Strain
Seroconversion against each strain contained in the seasonal quadrivalent influenza vaccine was measured by HAI antibody response. Seroconversion is defined as a four-fold rise in HAI post- compared to pre-vaccination, or a titer of ≥40 if the pre-vaccination titer was \<10.
Time frame: 180 days after vaccination
Geometric Mean Titers (GMTs) of Serum HAI Against Each Strain
The geometric scale is logarithmic. A geometric mean is calculated by averaging the logarithms of the test values and then converting the mean to a real number.
Time frame: 180 days after vaccination
The Proportion of Participants Achieving Seroprotection or Seroconversion Against Each Strain Measured by NAb Response
Seroprotection/seroconversion against each strain contained in the seasonal quadrivalent influenza vaccine will be measured by NAb antibody response.
Time frame: 180 days after vaccination
Geometric Mean Titers (GMTs) of Serum NAb Against Each Strain
The geometric scale is logarithmic. A geometric mean is calculated by averaging the logarithms of the test values and then converting the mean to a real number.
Time frame: 180 days after vaccination