Dataset Information

Using the Influenza Patient-reported Outcome (FLU-PRO) diary to evaluate symptoms of influenza viral infection in a healthy human challenge model.

ABSTRACT:

Background

In clinical studies involving a healthy volunteer human challenge model, a valid and reliable measure to assess the evolution of patient-reported symptom type and severity following viral exposure is necessary. This study examines the use of the InFLUenza Patient-Reported Outcome (FLU-PRO) diary as a standardized measure of symptom severity in a healthy volunteer human challenge model.

Methods

Healthy adults admitted to the NIH Clinical Center (Day - 1) underwent a 9-day inpatient quarantine after intranasal challenge with a wild-type influenza A/H1N1pdm virus (Day 0). Participants completed the 32-item FLU-PRO diary twice daily for 14 days to assess presence, severity, and duration of symptoms across six body systems. Secondary analyses included descriptive statistics to examine FLU-PRO scores over the course of illness and analysis of variance to compare scores on Day 3 post-challenge by presence of viral shedding, and pre-challenge hemagglutinin and neuraminidase inhibition (HAI and NAI) titers.

Results

All but one subject (99%), who was lost to follow-up, completed twice daily FLU-PRO diaries on all study assessment days. FLU-PRO demonstrated that 61 of 65 subjects reported symptoms (Days: Median 5, Mean 6 ± 7), of whom 37 (61%) had viral shedding. Pre-challenge, 39 (64%) and 10 (16%) subjects had low (< 1:40) HAI and NAI titers, respectively. Nose, throat, body, and gastrointestinal (GI) symptoms reached peak intensity at Day 3, followed by chest/respiratory and eye symptoms at Day 4. Subjects with viral shedding had higher mean FLU-PRO scores compared to those without, except for Eye and GI domains (p <0.05). Mean FLU-PRO scores were significantly higher for subjects with low NAI titer (p <0.05) across all domains. No significant differences were observed between HAI titer groups. FLU-PRO scores of the low HAI-low NAI group (n = 10) were significantly higher (more severe) than the other two groups (p < 0.05) (high HAI-high NAI (n = 22), low HAI-high NAI (n = 29)).

Conclusions

The FLU-PRO had high adherence and low respondent burden. It can be used to track symptom onset, intensity, duration, and recovery from influenza infection in clinical research. In this human challenge study, scores were responsive to change and distinguished known clinical subgroups.

Trial registration

NCT01971255 First Registered October 2, 2013.

SUBMITTER: Han A

PROVIDER: S-EPMC6064178 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature

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Publications

Using the Influenza Patient-reported Outcome (FLU-PRO) diary to evaluate symptoms of influenza viral infection in a healthy human challenge model.

Han Alison A Poon Jiat-Ling JL Powers John H JH Leidy Nancy K NK Yu Ren R Memoli Matthew J MJ

BMC infectious diseases 20180728 1

<h4>Background</h4>In clinical studies involving a healthy volunteer human challenge model, a valid and reliable measure to assess the evolution of patient-reported symptom type and severity following viral exposure is necessary. This study examines the use of the InFLUenza Patient-Reported Outcome (FLU-PRO) diary as a standardized measure of symptom severity in a healthy volunteer human challenge model.<h4>Methods</h4>Healthy adults admitted to the NIH Clinical Center (Day - 1) underwent a 9-da ...[more]

PMID: 30055573

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Project description:BackgroundThe inFLUenza Patient Reported Outcome (FLU-PRO) measure is a daily diary assessing signs/symptoms of influenza across six body systems: Nose, Throat, Eyes, Chest/Respiratory, Gastrointestinal, Body/Systemic, developed and tested in adults with influenza.ObjectivesThis study tested the reliability, validity, and responsiveness of FLU-PRO scores in adults with influenza-like illness (ILI).MethodsData from the prospective, observational study used to develop and test the FLU-PRO in influenza virus positive patients were analyzed. Adults (≥18 years) presenting with influenza symptoms in outpatient settings in the US, UK, Mexico, and South America were enrolled, tested for influenza virus, and asked to complete the 37-item draft FLU-PRO daily for up to 14-days. Analyses were performed on data from patients testing negative. Reliability of the final, 32-item FLU-PRO was estimated using Cronbach's alpha (α; Day 1) and intraclass correlation coefficients (ICC; 2-day reproducibility). Convergent and known-groups validity were assessed using patient global assessments of influenza severity (PGA). Patient report of return to usual health was used to assess responsiveness (Day 1-7).ResultsThe analytical sample included 220 ILI patients (mean age = 39.3, 64.1% female, 88.6% white). Sixty-one (28%) were hospitalized at some point in their illness. Internal consistency reliability (α) of FLU-PRO Total score was 0.90 and ranged from 0.72-0.86 for domain scores. Reproducibility (Day 1-2) was 0.64 for Total, ranging from 0.46-0.78 for domain scores. Day 1 FLU-PRO scores correlated (≥0.30) with the PGA (except Gastrointestinal) and were significantly different across PGA severity groups (Total: F = 81.7, p<0.001; subscales: F = 6.9-62.2; p<0.01). Mean score improvements Day 1-7 were significantly greater in patients reporting return to usual health compared with those who did not (p<0.05, Total and subscales, except Gastrointestinal and Eyes).ConclusionsResults suggest FLU-PRO scores are reliable, valid, and responsive in adults with influenza-like illness.

Project description:ObjectivesTo assess the reliability, validity, and responsiveness of InFLUenza Patient-Reported Outcome (FLU-PRO©) scores for quantifying the presence and severity of influenza symptoms.MethodsAn observational prospective cohort study of adults (≥18 years) with influenza-like illness in the United States, the United Kingdom, Mexico, and South America was conducted. Participants completed the 37-item draft FLU-PRO daily for up to 14 days. Item-level and factor analyses were used to remove items and determine factor structure. Reliability of the final tool was estimated using Cronbach α and intraclass correlation coefficients (2-day reliability). Convergent and known-groups validity and responsiveness were assessed using global assessments of influenza severity and return to usual health.ResultsOf the 536 patients enrolled, 221 influenza-positive subjects comprised the analytical sample. The mean age of the patients was 40.7 years, 60.2% were women, and 59.7% were white. The final 32-item measure has six factors/domains (nose, throat, eyes, chest/respiratory, gastrointestinal, and body/systemic), with a higher order factor representing symptom severity overall (comparative fit index = 0.92; root mean square error of approximation = 0.06). Cronbach α was high (total = 0.92; domain range = 0.71-0.87); test-retest reliability (intraclass correlation coefficient, day 1-day 2) was 0.83 for total scores and 0.57 to 0.79 for domains. Day 1 FLU-PRO domain and total scores were moderately to highly correlated (≥0.30) with Patient Global Rating of Flu Severity (except nose and throat). Consistent with known-groups validity, scores differentiated severity groups on the basis of global rating (total: F = 57.2, P < 0.001; domains: F = 8.9-67.5, P < 0.001). Subjects reporting return to usual health showed significantly greater (P < 0.05) FLU-PRO score improvement by day 7 than did those who did not, suggesting score responsiveness.ConclusionsResults suggest that FLU-PRO scores are reliable, valid, and responsive to change in influenza-positive adults.

Project description:The induction of systemic antibody titers against hemagglutinin has long been the main focus of influenza vaccination strategies, but mucosal immunity has also been shown to play a key role in the protection against respiratory viruses. By vaccinating and challenging healthy volunteers, we demonstrated that inactivated influenza vaccine (IIV) modestly reduced the rate of influenza while predominantly boosting serum antibody titers against hemagglutinin (HA) and HA stalk, a consequence of the low neuraminidase (NA) content of IIV and the intramuscular route of administration. The viral challenge induced nasal and serum responses against both HA and NA. Correlations between mucosal IgA and serum IgG against specific antigens were low, whether before or after challenge, suggesting a compartmentalization of immune responses. Even so, volunteers who developed viral shedding for multiple days had lower baseline titers across both systemic and mucosal compartments as compared to those with no shedding or a single day of shedding. Regression analysis showed that pre-challenge HA inhibition titers were the most consistent correlate of protection across clinical outcomes combining shedding and symptoms, with NA inhibition titers and HA IgG levels only predicting the duration of shedding. Despite the inclusion of data from multiple binding and functional antibody assays against HA and NA performed on both serum and nasal samples, multivariate models were unable to account for the variability in outcomes, emphasizing our imperfect understanding of immune correlates in influenza and the importance of refining models with assessments of innate and cellular immune responses.IMPORTANCEThe devastating potential of influenza has been well known for over 100 years. Despite the development of vaccines since the middle of the 20th century, influenza continues to be responsible for substantial global morbidity and mortality. To develop next-generation vaccines with enhanced effectiveness, we must synthesize our understanding of the complex immune mechanisms culminating in protection. Our study outlines the differences in immune responses to influenza vaccine and influenza infection, identifying potential gaps in vaccine-induced immunity, particularly at the level of the nasal mucosa. Furthermore, this research underscores the need to refine our imperfect models while recognizing potential pitfalls in past and future attempts to identify and measure correlates of protection.

Dataset Information

Using the Influenza Patient-reported Outcome (FLU-PRO) diary to evaluate symptoms of influenza viral infection in a healthy human challenge model.

Background

Methods

Results

Conclusions

Trial registration

Publications

Using the Influenza Patient-reported Outcome (FLU-PRO) diary to evaluate symptoms of influenza viral infection in a healthy human challenge model.

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