This is a study of a reverse-engineered, Good Manufacturing Practice (GMP) grade, antiviral-sensitive, influenza A/Bethesda/MM2/H1N1 virus (A/California/04/2009/H1N1-like) infection to assess the effect of pre-existing immunity on clinical and immunological responses. Up to 80 healthy adult subjects will undergo intranasal inoculation with A/Bethesda/MM2/H1N1 virus, and their clinical manifestations, viral shedding and immunological responses will be characterized. The Primary Objective for this study is to evaluate the association of symptomatic Reverse Transcription-Polymerase Chain Reaction (RT-PCR)-positive influenza virus infection post-challenge and pre-existing Hemagglutinin Inhibition Test (HAI) antibody titers.
This is a study of a reverse-engineered, Good Manufacturing Practice (GMP) grade, antiviral-sensitive, influenza A/Bethesda/MM2/H1N1 virus (A/California/04/2009/H1N1-like) infection to assess the effect of pre-existing immunity on clinical and immunological responses. Up to 80 healthy adult subjects will undergo intranasal inoculation with A/Bethesda/MM2/H1N1 virus, and their clinical manifestations, viral shedding and immunological responses will be characterized. This proposed study will establish a H1N1 influenza virus controlled human infection (CHI) model at the National Institute of Allergy and Infectious Diseases (NIAID) Division of Microbiology and Infectious Diseases (DMID)-sponsored Vaccine and Treatment Evaluation Units (VTEU) clinical study sites. The model has been developed and used by NIAID Division of Intramural Research. The proposed study will expand US research capacity to perform influenza CHI studies to advance the understanding of influenza pathogenesis and novel vaccine research and development. The Primary Objective for this study is to evaluate the association of symptomatic Reverse Transcription-Polymerase Chain Reaction (RT-PCR)-positive influenza virus infection post-challenge and pre-existing Hemagglutinin Inhibition Test (HAI) antibody titers. The Secondary Objectives for this study are: 1) To describe viral recovery by quantitative RT-PCR from study subjects at baseline and post-challenge; 2) To describe serum HAI and MN antibody responses post-challenge in healthy subjects by infection status; 3) To evaluate the association of asymptomatic RT-PCR-positive influenza virus infection (viral shedding) post-challenge and pre-existing HAI antibody titers; 4) To evaluate the association of symptomatic RT-PCR-negative status post-challenge and pre-existing HAI antibody titers; 5) To determine the frequency of serious adverse events (SAE) post-challenge.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
76
Reverse-genetics derived live A/California/04/2009/H1N1-like influenza virus passaged six times in Vero cells.
University of Maryland Baltimore - School of Medicine - Medicine
Baltimore, Maryland, United States
Saint Louis University - Center for Vaccine Development
St Louis, Missouri, United States
Duke Human Vaccine Institute - Duke Vaccine and Trials Unit
Durham, North Carolina, United States
Cincinnati Children's Hospital Medical Center - Infectious Diseases
Cincinnati, Ohio, United States
Percentage of Healthy Participants Reporting Mild-to-Moderate Influenza Disease (MMID) by Baseline A/Bethesda/MM2/H1N1 Hemagglutination Inhibition (HAI) Antibody Seroprotection Status (Titer >/= 1:40 vs. Titer < 1:40)
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). MMID is a composite endpoint determined by the presence of viral shedding (detected by any approved positive RT-PCR test from a NP swab), accompanied by at least one the following symptoms occurring any time from Day 2 through Day 8; body aches or pain, chest tightness, chills, conjunctivitis, nasal congestion, sinus congestion, coryza, decreased appetite, diarrhea, dry cough, dyspnea, fatigue, fever, headache, lymphopenia, nausea, a 3% or more decrease in oxygen saturation from baseline, productive cough, rhinorrhea, sore throat, and sweats. The percentage of participants that developed MMID was calculated within each pre-challenge seroprotection status group.
Time frame: Day 2 through Day 8
Association Between Clinical or Laboratory Manifestation of MMID and A/Bethesda/MM2/H1N1 HAI Antibodies in Serum at Baseline
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results. MMID is a composite endpoint determined by the presence of viral shedding (detected by any approved positive RT-PCR test from a NP swab), accompanied by at least one the following symptoms occurring any time from Day 2 through Day 8; body aches or pain, chest tightness, chills, conjunctivitis, nasal congestion, sinus congestion, coryza, decreased appetite, diarrhea, dry cough, dyspnea, fatigue, fever, headache, lymphopenia, nausea, a 3% or more decrease in oxygen saturation from baseline, productive cough, rhinorrhea, sore throat, and sweats. The relationship between the level of pre-challenge HAI titer and the likelihood of developing MMID during the study challenge period (Day 2 to Day 8) was assessed via logistic regression.
Time frame: Day 2 to Day 8
Geometric Mean Titer (GMT) of HAI Antibody in Serum at Baseline by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results. The geometric mean across samples was calculated within each study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day -2
GMT of HAI Antibody in Serum at Day 8 by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results. The geometric mean across samples was calculated within each study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day 8
GMT of HAI Antibody in Serum at Day 29 by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results. The geometric mean across samples was calculated within each study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day 29
GMT of HAI Antibody in Serum at Day 61 by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results. The geometric mean across samples was calculated within each study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
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Time frame: Day 61
Percentage of Healthy Participants Achieving HAI Seroconversion From Baseline in Serum at Day 8 by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. Seroconversion was defined as a pre-challenge titer 1:10 or greater and a minimum 4-fold rise in post-challenge antibody titer. The percentage of participants achieving seroconversion was calculated within each post-challenge study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day 8
Percentage of Healthy Participants Achieving HAI Seroconversion in Serum From Baseline at Day 29 by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. Seroconversion was defined as a pre-challenge titer 1:10 or greater and a minimum 4-fold rise in post-challenge antibody titer. The percentage of participants achieving seroconversion was calculated within each post-challenge study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day 29
Percentage of Healthy Participants Achieving HAI Seroconversion in Serum From Baseline at Day 61 by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. Seroconversion was defined as a pre-challenge titer 1:10 or greater and a minimum 4-fold rise in post-challenge antibody titer. The percentage of participants achieving seroconversion was calculated within each post-challenge study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day 61
GMT of Microneutralization (MN) Antibody in Serum at Baseline by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results. The geometric mean across samples was calculated within each study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day -2
GMT of MN Antibody in Serum at Day 8 by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results. The geometric mean across samples was calculated within each study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day 8
GMT of MN Antibody in Serum at Day 29 by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results. The geometric mean across samples was calculated within each study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day 29
GMT of MN Antibody in Serum at Day 61 by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results. The geometric mean across samples was calculated within each study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day 61
Percentage of Healthy Participants Achieving MN Seroconversion From Baseline in Serum at Day 8 by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. Seroconversion was defined as a pre-challenge titer 1:10 or greater and a minimum 4-fold rise in post-challenge antibody titer. The percentage of participants achieving seroconversion was calculated within each post-challenge study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day 8
Percentage of Healthy Participants Achieving MN Seroconversion From Baseline in Serum at Day 29 by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. Seroconversion was defined as a pre-challenge titer 1:10 or greater and a minimum 4-fold rise in post-challenge antibody titer. The percentage of participants achieving seroconversion was calculated within each post-challenge study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day 29
Percentage of Healthy Participants Achieving MN Seroconversion From Baseline in Serum at Day 61 by Infection Status
Blood samples were collected pre-challenge (Day -2) and post-challenge on Days 8, 29 and 61 for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. Seroconversion was defined as a pre-challenge titer 1:10 or greater and a minimum 4-fold rise in post-challenge antibody titer. The percentage of participants achieving seroconversion was calculated within each post-challenge study day and by infection status as observed over the study challenge period (Day 2 to Day 8); RT-PCR Negative (never positive), RT-PCR Positive Asymptomatic (participants with at least one positive PCR result but no symptoms reported), at least once RT-PCR Positive Symptomatic (or MMID).
Time frame: Day 61
Duration of Viral Shedding in Nasopharyngeal (NP) Swab by Baseline HAI Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). Duration of viral shedding (detected by any approved positive RT-PCR test from NP swab) was calculated from the day of the initial positive PCR result to the day of the last positive PCR result prior to discharge from the challenge unit facility, regardless of intermittent negative PCR results. The mean duration of viral shedding was calculated among participants with detected virus within each pre-challenge HAI seroprotection status group.
Time frame: Day 2 through Day 15
Duration of Viral Shedding in NP Swab by Baseline MN Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). Duration of viral shedding (detected by any approved positive RT-PCR test from NP swab) was calculated from the day of the initial positive PCR result to the day of the last positive PCR result prior to discharge from the challenge unit facility, regardless of intermittent negative PCR results. The mean duration of viral shedding was calculated among participants with detected virus within each pre-challenge MN seroprotection status group.
Time frame: Day 2 to Day 15
Number of Participants With Viral Shedding in NP Swab at Day 2 by Baseline HAI Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 2
Number of Participants With Viral Shedding in NP Swab at Day 3 by Baseline HAI Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 3
Number of Participants With Viral Shedding in NP Swab at Day 4 by Baseline HAI Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 4
Number of Participants With Viral Shedding in NP Swab at Day 5 by Baseline HAI Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 5
Number of Participants With Viral Shedding in NP Swab at Day 6 by Baseline HAI Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 6
Number of Participants With Viral Shedding in NP Swab at Day 7 by Baseline HAI Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 7
Number of Participants With Viral Shedding in NP Swab at Day 8 by Baseline HAI Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 8
Number of Participants With Viral Shedding in NP Swab Anytime Post-challenge by Baseline HAI Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 2 to Day 8
Number of Participants With Viral Shedding in NP Swab at Day 2 by Baseline MN Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 2
Number of Participants With Viral Shedding in NP Swab at Day 3 by Baseline MN Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 3
Number of Participants With Viral Shedding in NP Swab at Day 4 by Baseline MN Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 4
Number of Participants With Viral Shedding in NP Swab at Day 5 by Baseline MN Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 5
Number of Participants With Viral Shedding in NP Swab at Day 6 by Baseline MN Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 6
Number of Participants With Viral Shedding in NP Swab at Day 7 by Baseline MN Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 7
Number of Participants With Viral Shedding in NP Swab at Day 8 by Baseline MN Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 8
Number of Participants With Viral Shedding in NP Swab Anytime Post-challenge by Baseline MN Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated for available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The number of participants with viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated for each study day post-challenge (Day 2 to Day 8) and at any time during the entire challenge period within each pre-challenge seroprotection status group.
Time frame: Day 2 through Day 8
Time Until Detectable Viral Shedding in NP Swab by Baseline HAI Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). Time until viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated as the initial day of viral shedding post-challenge for each participant. Median time to viral shedding was calculated within each pre-challenge seroprotection status group via the Kaplan-Meier estimator.
Time frame: Day 2 through Day 8
Time Until Detectable Viral Shedding in NP Swab by Baseline MN Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). Time until viral shedding (detected by any approved positive RT-PCR test from a NP swab) was calculated as the initial day of viral shedding post-challenge for each participant. Median time to viral shedding was calculated within each pre-challenge seroprotection status group via the Kaplan-Meier estimator.
Time frame: Day 2 through Day 8
Magnitude of Viral Shedding in NP Swab by Baseline HAI Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The quantity of viral load copies/mL from NP swab was measured via quantitative RT-PCR result for each post-challenge study day. The mean of each sample's quantitative PCR replicate results was calculated from available results. Total viral shedding, as observed until study discharge, was calculated as the area under the curve (AUC), then log-10 transformed. Peak viral shedding was calculated as the maximum viral load copies/mL observed until study discharge, then log-10 transformed. The mean and median of the log-10 AUC and the mean and median of the log-10 peak viral load were both calculated within each pre-challenge seroprotection status group.
Time frame: Day 2 through Day 15
Magnitude of Viral Shedding in NP Swab by Baseline MN Seroprotection Status
Blood samples were collected pre-challenge (Day -2) for the MN assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The quantity of viral load copies/mL from NP swab was measured via quantitative RT-PCR result for each post-challenge study day. The mean of each sample's quantitative PCR replicate results was calculated from available results. Total viral shedding, as observed until study discharge, was calculated as the area under the curve (AUC), then log-10 transformed. Peak viral shedding was calculated as the maximum viral load copies/mL observed until study discharge, then log-10 transformed. The mean and median of the log-10 AUC and the mean and median of the log-10 peak viral load were both calculated within each pre-challenge seroprotection status group.
Time frame: Day 2 through Day 15
Percentage of Participants Reporting Any MMID Symptom During Challenge Period by Viral Shedding Status and Baseline HAI Seroprotection Status From Serum Measured at Baseline - RT-PCR Positive (One or More)
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The presence of any of the following symptoms was assessed from Day 2 to Day 8; body aches or pain, chest tightness, chills, conjunctivitis, nasal congestion, sinus congestion, coryza, decreased appetite, diarrhea, dry cough, dyspnea, fatigue, fever, headache, lymphopenia, nausea, a 3% or more decrease in oxygen saturation from baseline, productive cough, rhinorrhea, sore throat, and sweats. The percentage of participants that reported any symptom was calculated within each pre-challenge seroprotection status group and by viral shedding status, as observed anytime from Day 2 to Day 8; RT-PCR Negative (never positive), and at least once RT-PCR Positive.
Time frame: Day 2 through Day 8
Percentage of Participants Reporting Any MMID Symptom During Challenge Period by Viral Shedding Status and Baseline HAI Seroprotection Status From Serum Measured at Baseline With RT-PCR Negative (None Positive)
Blood samples were collected pre-challenge (Day -2) for the HAI assay conducted with the A/Bethesda/MM2/H1N1 virus as the antigen. The geometric mean of each sample's replicate results was calculated from available results, then grouped by seroprotection status (titer results \>= 1:40 vs \< 1:40). The presence of any of the following symptoms was assessed from Day 2 to Day 8; body aches or pain, chest tightness, chills, conjunctivitis, nasal congestion, sinus congestion, coryza, decreased appetite, diarrhea, dry cough, dyspnea, fatigue, fever, headache, lymphopenia, nausea, a 3% or more decrease in oxygen saturation from baseline, productive cough, rhinorrhea, sore throat, and sweats. The percentage of participants that reported any symptom was calculated within each pre-challenge seroprotection status group and by viral shedding status, as observed anytime from Day 2 to Day 8; RT-PCR Negative (never positive), and at least once RT-PCR Positive.
Time frame: Day 2 through Day 8
Number of Serious Adverse Events (SAE) Post-challenge Through the Inpatient Stay
SAEs included any untoward medical occurrence that resulted in death or a congenital anomaly/birth defect; was life threatening or a persistent/significant disability/incapacity; required inpatient hospitalization or prolongation of existing hospitalization. All events are included regardless of relationship to the study challenge.
Time frame: Day 1 through Day 8
Number of Serious Adverse Events (SAE) Post- Inpatient Discharge Through the Duration of the Study
SAEs included any untoward medical occurrence that resulted in death or a congenital anomaly/birth defect; was life threatening or a persistent/significant disability/incapacity; required inpatient hospitalization or prolongation of existing hospitalization. All events are included regardless of relationship to the study challenge.This table provides the number and percentage of participants who reported SAEs following discharge from the study hospital.
Time frame: Day 9 through Day 91