Human InfluenzaTransFLUasNCT02478905
Transmission of Influenza Virus From Asymptomatic Healthcare Workers and Inpatients in the Acute Care Hospital Setting
An observational study of Human Influenza, run by University of Zurich at 1 site in Switzerland.
Trial summary
The epidemiology and transmission dynamics of influenza in hospitals are only poorly understood, particularly with respect to subjects without symptoms of influenza infection (e.g. without fever, cough, sore throat, nasal congestion, weakness, headache, loss of appetite, or myalgia). Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Human Influenza
- What is being tested?
- Influenza
- How many people
- 700 participants
- Where
- 1 siteSwitzerland
- Study dates
- Jan 2016to Jun 2017
- How long will I take part?
- 1 Year
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: This project is a prospective study following patients in medical wards and acute care HCW (including nursing staff (nurses and assistant nurses), physiotherapists, house staff with direct patient contact and medical doctors (clinical fellows) working on the same wards at the University Hospital Zurich. Inpatients and HCW will be recruited from general medical and infectious diseases wards, pulmonology wards, hematology wards and from the stem cell transplant unit. All HCW and inpatients on the ward under surveillance are eligible for the study
Who may be able to join
- 18 or more years of age;
- Available for follow-up during the study period;
- If a HCW: employed full- or part-time (≥50% full-time equivalent);
- Understand the study, agree to its provisions, and give written informed consent (as documented by signature).
Who cannot join
- If a HCW: planning to spend more than two consecutive weeks outside of Switzerland during the winter study period (November 1st to April 31st);
- If a HCW: planning to take leave from work for more than two consecutive weeks during the winter study period (e.g. maternity or medical leave);
- Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders or dementia of the subject;
- Known or suspected non-compliance.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: TransFLUas: Transmission of Influenza Virus From Asymptomatic Healthcare Workers and Inpatients in the Acute Care Hospital Setting: A Prospective Study Over Two Consecutive Influenza Seasons
The epidemiology and transmission dynamics of influenza in hospitals are only poorly understood, particularly with respect to subjects without symptoms of influenza infection (e.g. without fever, cough, sore throat, nasal congestion, weakness, headache, loss of appetite, or myalgia). Knowledge about whether asymptomatic subjects are able to transmit influenza is of major importance. If they do transmit influenza, vaccination of patients and healthcare workers (HCW) before start of the influenza season, the permanent use of masks by HCW during influenza season, and quarantine for previously exposed inpatients may be the only available measures to reduce the number of influenza transmission events from asymptomatic subjects in acute care hospitals. Closure of this knowledge gap would be of major benefit to infection prevention and control recommendations, and may in turn reduce morbidity and mortality associated with influenza in hospitals through improved patient management.
Read the detailed description
The epidemiology and transmission dynamics of influenza in hospitals are only poorly understood, particularly with respect to subjects without symptoms of influenza infection (e.g. without fever, cough, sore throat, nasal congestion, weakness, headache, loss of appetite, or myalgia). Knowledge about whether asymptomatic subjects are able to transmit influenza is of major importance. If they do transmit influenza, vaccination of patients and healthcare workers (HCW) before start of the influenza season, the permanent use of masks by HCW during influenza season, and quarantine for previously exposed inpatients may be the only available measures to reduce the number of influenza transmission events from asymptomatic subjects in acute care hospitals.
The investigators' key aim is therefore to define whether exposure to asymptomatic subjects with influenza infection constitutes a risk for influenza transmission in an acute care hospital setting through active, prospective surveillance.
The investigators' secondary aims are to describe the prevalence of community-acquired symptomatic and asymptomatic influenza upon hospital admission and the incidence of asymptomatic and symptomatic nosocomial influenza among inpatients; to assess transmission dynamics of symptomatic influenza infection in acute care; and to study the incidence of asymptomatic and symptomatic influenza, absenteeism (i.e. being absent from work due to influenza), presenteeism (i.e. being present at work despite influenza infection) associated with influenza, and compliance with infection control recommendations to prevent spread of influenza in acute care HCW.
The investigators plan to enroll 1,260 inpatients and 180 HCW from medical wards at the University Hospital Zurich in a prospective study over two consecutive influenza seasons in order to detect at least one transmission event from an asymptomatic individual shedding influenza virus. Flocked mid-turbinate nasal swabs will be collected daily from consenting inpatients starting from day of admission until two days after discharge and from HCW over the influenza (winter) season and analyzed for influenza A and B using polymerase chain reaction. Simultaneously, signs and symptoms of influenza infection (including cough, sore throat, fever >37.8°C, nasal congestion, weakness, headache, loss of appetite or myalgia) as well as contact patterns between inpatients and HCW will be recorded. Reconstruction of influenza transmission chains will be based on phylogenetic analyses derived from next-generation sequence data and epidemiological contact tracing.
- Conditions
- Human Influenza
- Being tested
- Influenza
- Medical subject headings
- Influenza, Human
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
InfluenzaOther
| Study group | Role | What they receive |
|---|---|---|
| surveillance cohort | Flocked mid-turbinate nasal swabs for influenza PCR will be collected from study participants daily Receives: Other: Influenza |
What is being measured
The primary outcome is the main question the study is designed to answer.
Secondary attack rate of asymptomatic or presymptomatic influenza among inpatients, among acute care workers and between inpatients and acute care HCW in an acute care hospital setting
diagnosed by positive influenza PCR from flocked mid-turbinate nasal swab collected in symptomatic or asymptomatic individuals following face-to-face contact with an individual with symptomatic influenza infection on the day of contact.
Measured: up to 6 months
Secondary outcomes (11)
Secondary attack rate of symptomatic influenza among inpatients, among acute care workers and between inpatients and acute care HCW in an acute care hospital setting
Secondary attack rate of symptomatic influenza among inpatients, among acute care workers and between inpatients and acute care HCW in an acute care hospital setting: as diagnosed by positive influenza PCR from flocked mid-turbinate nasal swab collected in symptomatic or asymptomatic individuals following face-to-face contact with an individual with symptomatic influenza infection on the day of contact. Transmissions will be considered 'proven' if confirmed by phylogenetic analyses. Specifically, we expect that whole-genome sequence analysis will demonstrate identical or almost identical influenza strains within transmission chains.
Transmissions will be considered 'probable' if there is epidemiological evidence of face-to-face contact and identical strains have been identified in PCR but whole-genome sequencing was technically unsuccessful;
Measured: up to 6 months
Proportion of asymptomatic and symptomatic inpatients with influenza infection upon hospital admission: as diagnosed by influenza polymerase chain reaction (PCR) from flocked mid-turbinate nasal swabs collected upon hospital admission
diagnosed by influenza PCR from flocked mid-turbinate nasal swabs collected upon hospital admission
Measured: up to 6 months
Incidence of asymptomatic (A5) and symptomatic (A6) nosocomial influenza in hospital inpatients, defined as the number of emerging influenza infections >72 hours after hospital admissions per 100 patient-days
diagnosed by PCR from flocked mid-turbinate nasal swabs collected three times per week over the influenza season
Measured: up to 6 months
Incidence of asymptomatic (A7) and symptomatic (A8) influenza in acute care hospital workers defined as the number of influenza infections per 100 HCW per influenza season
diagnosed by influenza PCR from flocked mid-turbinate nasal swabs collected three times per week over the influenza season collected three times per week over the influenza season
Measured: up to 6 months
Association of individual influenza symptoms with influenza transmission from subjects with symptomatic influenza infection
Association of individual influenza symptoms with influenza transmission from subjects with symptomatic influenza infection
Measured: up to 6 months
Influenza-attributable mortality in inpatients, expressed as infection-fatality rate, i.e. number of deaths among those infected
number of deaths among those infected
Measured: up to 6 months
Absenteeism: as defined by total number of days absent from work due to PCR-proven influenza divided by total number of days due to work in HCW
Absenteeism: as defined by total number of days absent from work due to PCR-proven influenza divided by total number of days due to work in HCW;
Measured: up to 6 months
Presenteeism: as defined by total number of days with symptoms of influenza present at work divided by total number of days due to work in HCW with PCR-proven influenza infection
Presenteeism: as defined by total number of days with symptoms of influenza present at work divided by total number of days due to work in HCW with PCR-proven influenza infection;
Measured: up to 6 months
Compliance with hand hygiene recommendations and cough etiquette (including barrier precautions) in HCW according to repeated observations
Compliance with hand hygiene recommendations and cough etiquette (including barrier precautions) in HCW according to repeated observations;
Measured: up to 6 months
Association of patient and HCW characteristics, including receipt of influenza vaccine, with asymptomatic viral shedding, as compared to symptomatic shedding
Association of patient and HCW characteristics, including receipt of influenza vaccine, with asymptomatic viral shedding, as compared to symptomatic shedding;
Measured: up to 6 months
Association between viral load and asymptomatic or symptomatic transmission based on quantification of viral shedding according to cycle threshold (Ct) values from PCR
defined as the number of cycles required for the fluorescent signal to cross the threshold (i.e. exceeds background level).
Measured: up to 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Jun 2015 (estimated)
- Study startJan 2016
- Primary completionJun 2017
- Study completionJun 2017
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Human InfluenzaStudies of the same condition, open and under way.
- More trials run by University of ZurichThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 700 participants (actual)
- Target duration
- 1 Year
Sponsor and investigators
- Lead sponsor
- University of Zurich
- Sponsor type
- University, hospital or other
- Collaborators
- Schweizerischer Nationalfonds
- Responsible party
- Sponsor
- Investigators
- Stefan Kuster, MD, Principal investigator, Division of Infectious Diseases and Hospital Epidemiology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02478905
- Sponsor's protocol ID
- KEK-ZH-Nr. 2015-0228
- Acronym
- TransFLUas
- Status last verified
- Oct 2017
- First submitted
- 5 Jun 2015
- Last updated
- 31 Oct 2017
- Results posted
- No
- Data monitoring committee
- No
Publications
Kuster SP, Boni J, Kouyos RD, Huber M, Schmutz S, Shah C, Bischoff-Ferrari HA, Distler O, Battegay E, Giovanoli P, Guckenberger M, Kohler M, Muller R, Petry H, Ruschitzka F, McGeer A, Coleman BL, Sax H, Weber R, Trkola A. Absenteeism and presenteeism in healthcare workers due to respiratory illness. Infect Control Hosp Epidemiol. 2021 Mar;42(3):268-273. doi: 10.1017/ice.2020.444. Epub 2020 Nov 26.
PubMed 33239124Schwarz H, Boni J, Kouyos RD, Turk T, Battegay E, Kohler M, Muller R, Petry H, Sax H, Weber R, McGeer A, Trkola A, Kuster SP. The TransFLUas influenza transmission study in acute healthcare - recruitment rates and protocol adherence in healthcare workers and inpatients. BMC Infect Dis. 2019 May 21;19(1):446. doi: 10.1186/s12879-019-4057-5.
PubMed 31113375
Study at a glance
From the registry record, last updated by the sponsor on 31 Oct 2017. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- TransFLUas: Transmission of Influenza Virus From Asymptomatic Healthcare Workers and Inpatients in the Acute Care Hospital Setting: A Prospective Study Over Two Consecutive Influenza Seasons
- ClinicalTrials.gov ID
- NCT02478905
- Acronym / sponsor ID
- TransFLUas / KEK-ZH-Nr. 2015-0228
- Conditions
- Human Influenza
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 700 participants (actual)
- Lead sponsor
- University of ZurichUniversity, hospital or other
- Collaborators
- Schweizerischer Nationalfonds
- Study start
- Jan 2016
- Primary completion
- Jun 2017 (actual)
- Study completion
- Jun 2017 (actual)
- First posted
- 23 Jun 2015 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The epidemiology and transmission dynamics of influenza in hospitals are only poorly understood, particularly with respect to subjects without symptoms of influenza infection (e.g. without fever, cough, sore throat, nasal congestion, weakness, headache, loss of appetite, or myalgia). Knowledge about whether asymptomatic subjects are able to transmit influenza is of major importance. If they do transmit influenza, vaccination of patients and healthcare workers (HCW) before start of the influenza season, the permanent use of masks by HCW during influenza season, and quarantine for previously exposed inpatients may be the only available measures to reduce the number of influenza transmission events from asymptomatic subjects in acute care hospitals. Closure of this knowledge gap would be of major benefit to infection prevention and control recommendations, and may in turn reduce morbidity and mortality associated with influenza in hospitals through improved patient management.
Detailed description
The epidemiology and transmission dynamics of influenza in hospitals are only poorly understood, particularly with respect to subjects without symptoms of influenza infection (e.g. without fever, cough, sore throat, nasal congestion, weakness, headache, loss of appetite, or myalgia). Knowledge about whether asymptomatic subjects are able to transmit influenza is of major importance. If they do transmit influenza, vaccination of patients and healthcare workers (HCW) before start of the influenza season, the permanent use of masks by HCW during influenza season, and quarantine for previously exposed inpatients may be the only available measures to reduce the number of influenza transmission events from asymptomatic subjects in acute care hospitals.
The investigators' key aim is therefore to define whether exposure to asymptomatic subjects with influenza infection constitutes a risk for influenza transmission in an acute care hospital setting through active, prospective surveillance.
The investigators' secondary aims are to describe the prevalence of community-acquired symptomatic and asymptomatic influenza upon hospital admission and the incidence of asymptomatic and symptomatic nosocomial influenza among inpatients; to assess transmission dynamics of symptomatic influenza infection in acute care; and to study the incidence of asymptomatic and symptomatic influenza, absenteeism (i.e. being absent from work due to influenza), presenteeism (i.e. being present at work despite influenza infection) associated with influenza, and compliance with infection control recommendations to prevent spread of influenza in acute care HCW.
The investigators plan to enroll 1,260 inpatients and 180 HCW from medical wards at the University Hospital Zurich in a prospective study over two consecutive influenza seasons in order to detect at least one transmission event from an asymptomatic individual shedding influenza virus. Flocked mid-turbinate nasal swabs will be collected daily from consenting inpatients starting from day of admission until two days after discharge and from HCW over the influenza (winter) season and analyzed for influenza A and B using polymerase chain reaction. Simultaneously, signs and symptoms of influenza infection (including cough, sore throat, fever >37.8°C, nasal congestion, weakness, headache, loss of appetite or myalgia) as well as contact patterns between inpatients and HCW will be recorded. Reconstruction of influenza transmission chains will be based on phylogenetic analyses derived from next-generation sequence data and epidemiological contact tracing.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 1 Year
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| surveillance cohort | – | Other: InfluenzaFlocked mid-turbinate nasal swabs for influenza PCR will be collected from study participants daily |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- This project is a prospective study following patients in medical wards and acute care HCW (including nursing staff (nurses and assistant nurses), physiotherapists, house staff with direct patient contact and medical doctors (clinical fellows) working on the same wards at the University Hospital Zurich. Inpatients and HCW will be recruited from general medical and infectious diseases wards, pulmonology wards, hematology wards and from the stem cell transplant unit. All HCW and inpatients on the ward under surveillance are eligible for the study
Key inclusion criteria (4 listed)
- 18 or more years of age;
- Available for follow-up during the study period;
- If a HCW: employed full- or part-time (≥50% full-time equivalent);
- Understand the study, agree to its provisions, and give written informed consent (as documented by signature).
Key exclusion criteria (4 listed)
- If a HCW: planning to spend more than two consecutive weeks outside of Switzerland during the winter study period (November 1st to April 31st);
- If a HCW: planning to take leave from work for more than two consecutive weeks during the winter study period (e.g. maternity or medical leave);
- Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders or dementia of the subject;
- Known or suspected non-compliance.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Influenza | Other | surveillance cohort |
Primary outcome
Secondary attack rate of asymptomatic or presymptomatic influenza among inpatients, among acute care workers and between inpatients and acute care HCW in an acute care hospital setting
Time frame: up to 6 months
diagnosed by positive influenza PCR from flocked mid-turbinate nasal swab collected in symptomatic or asymptomatic individuals following face-to-face contact with an individual with symptomatic influenza infection on the day of contact.
11 secondary outcomes
Secondary attack rate of symptomatic influenza among inpatients, among acute care workers and between inpatients and acute care HCW in an acute care hospital setting
Time frame: up to 6 months
Proportion of asymptomatic and symptomatic inpatients with influenza infection upon hospital admission: as diagnosed by influenza polymerase chain reaction (PCR) from flocked mid-turbinate nasal swabs collected upon hospital admission
Time frame: up to 6 months
Incidence of asymptomatic (A5) and symptomatic (A6) nosocomial influenza in hospital inpatients, defined as the number of emerging influenza infections >72 hours after hospital admissions per 100 patient-days
Time frame: up to 6 months
Incidence of asymptomatic (A7) and symptomatic (A8) influenza in acute care hospital workers defined as the number of influenza infections per 100 HCW per influenza season
Time frame: up to 6 months
Association of individual influenza symptoms with influenza transmission from subjects with symptomatic influenza infection
Time frame: up to 6 months
Influenza-attributable mortality in inpatients, expressed as infection-fatality rate, i.e. number of deaths among those infected
Time frame: up to 6 months
Absenteeism: as defined by total number of days absent from work due to PCR-proven influenza divided by total number of days due to work in HCW
Time frame: up to 6 months
Presenteeism: as defined by total number of days with symptoms of influenza present at work divided by total number of days due to work in HCW with PCR-proven influenza infection
Time frame: up to 6 months
Compliance with hand hygiene recommendations and cough etiquette (including barrier precautions) in HCW according to repeated observations
Time frame: up to 6 months
Association of patient and HCW characteristics, including receipt of influenza vaccine, with asymptomatic viral shedding, as compared to symptomatic shedding
Time frame: up to 6 months
Association between viral load and asymptomatic or symptomatic transmission based on quantification of viral shedding according to cycle threshold (Ct) values from PCR
Time frame: up to 6 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 31 Oct 2017.
- Derived from this study: PubMed 33239124Kuster SP, Boni J, Kouyos RD, Huber M, Schmutz S, Shah C, Bischoff-Ferrari HA, Distler O, Battegay E, Giovanoli P, Guckenberger M, Kohler M, Muller R, Petry H, Ruschitzka F, McGeer A, Coleman BL, Sax H, Weber R, Trkola A. Absenteeism and presenteeism in healthcare workers due to respiratory illness. Infect Control Hosp Epidemiol. 2021 Mar;42(3):268-273. doi: 10.1017/ice.2020.444. Epub 2020 Nov 26.
- Derived from this study: PubMed 31113375Schwarz H, Boni J, Kouyos RD, Turk T, Battegay E, Kohler M, Muller R, Petry H, Sax H, Weber R, McGeer A, Trkola A, Kuster SP. The TransFLUas influenza transmission study in acute healthcare - recruitment rates and protocol adherence in healthcare workers and inpatients. BMC Infect Dis. 2019 May 21;19(1):446. doi: 10.1186/s12879-019-4057-5.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Stefan Kuster, MD principal investigator
Division of Infectious Diseases and Hospital Epidemiology
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Human Influenza, run by University of Zurich at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 31 Oct 2017. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Secondary attack rate of asymptomatic or presymptomatic influenza among inpatients, among acute care workers and between inpatients and acute care HCW in an acute care hospital setting (time frame: up to 6 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT02478905, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 31 Oct 2017.