Long-term Observation of Hemagglutinin and Neuraminidase Inhibition Antibody Titers After Influenza Challenge
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|ClinicalTrials.gov Identifier: NCT02511002|
Recruitment Status : Enrolling by invitation
First Posted : July 29, 2015
Last Update Posted : September 21, 2022
- Influenza is a common viral infection. But it can be deadly for some people. Researchers want to learn more about how the body fights this virus. They want to study this in people who have recently been infected with influenza. They hope this can help them create more effective influenza vaccines.
- To learn about long-term changes in the body s immune system after influenza infection.
- People who have completed a previous LID Clinical Studies Unit influenza challenge study and are willing to have samples stored for future research.
- Eligible participants will be asked to visit the clinic every 3 months for 2 years.
- During each visit, participants will have blood drawn from an arm vein using a needle and a syringe.
- Participants will have a medical history and physical exam and vital signs performed. This will include blood pressure, heart rate, breathing rate, temperature, weight, and finger-measured blood oxygen. They will answer questions about any medicines taken and possible recent illnesses.
- If participants have symptoms of influenza, they may have a sample taken from the nose. A small <TAB>amount of salt water will be sprayed into the nostril with a squeezable container. The salt water will then run out of the nose and into the container. Or the inside of the nose will be wiped with a swab that is
similar to a Q-tip.
- Participants will complete a health questionnaire once a month on a secure website. Participants may also give their responses over the telephone.
|Condition or disease|
Circulating anti-influenza antibodies are an important factor in predicting clinical illness and severity in those infected with influenza. Specific antibodies against influenza include proteins targeting hemagglutinin (HA) and neuraminidase (NA). Lifelong immunity does not occur with influenza, either from natural infection or from vaccination. Due to the antigenic variation of Influenza A, individuals may become infected multiple times with the same subtype of influenza and even with the same strain. In the setting of natural infection and vaccination, antibody titer levels can persist initially, but then wane over time.
In our previous challenge studies, measurements of antibody responses have been focused solely on the acute infection period up to 2 months after initial infection. Long-term changes in immunity have not been investigated. The challenge setting gives us the unique ability to follow individuals from a specific, known and well-characterized exposure/illness to measure long-term changes in antibody titers from a pre-exposure baseline. This study could offer unique insight into how anti-influenza antibody titers change over time naturally and in response to other infections and life events. This type of controlled study has never been done and we believe monitoring titers long-term will help us better understand protective correlates of influenza.
In this natural history study, we will follow individuals who have undergone influenza challenge or have been naturally infected with influenza to evaluate changes in anti-influenza antibody titers over a 2-year period. Subjects will be followed for symptoms of influenza-like illness (ILI) and other changes in clinical status through quarterly clinical evaluations with blood draws. Monthly questionnaires will be used to follow subjects in between visits.
|Study Type :||Observational|
|Estimated Enrollment :||200 participants|
|Official Title:||Long-Term Observation of Hemagglutinin and Neuraminidase Inhibition Antibody Titers After Influenza Challenge|
|Actual Study Start Date :||July 17, 2015|
|Estimated Primary Completion Date :||May 12, 2027|
|Estimated Study Completion Date :||May 12, 2027|
Post influenza infection
- To characterize the timing of peak antibody response to hemagglutinin (HA) and neuraminidase (NA) post influenza challenge or after natural infection To evaluate the long-term variability of hemagglutinin inhibition (HAI) and neuraminidase inhib... [ Time Frame: 2 years ]Trend of HAI titer over multiple time points Trend of NAI titer over multiple time points
- To correlate changes in clinical status such as influenza-like illness (ILI) or vaccinations with changes in antibody titers and other immune measures [ Time Frame: 2 years ]Change in HAI titer before and after change in clinical status Change in NAI titer before and after change in clinical status
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02511002
|United States, Maryland|
|National Institutes of Health Clinical Center|
|Bethesda, Maryland, United States, 20892|
|Principal Investigator:||Alison Han, M.D.||National Institute of Allergy and Infectious Diseases (NIAID)|