Study to Evaluate the Incidence, Clinical Characteristics and Economic Burden of Dengue in Brazilian Children

Study Overview
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Brief Summary
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The aim of this study is to establish an active surveillance in order to generate dengue disease burden estimates including incidence rates, prevalence data, clinical presentation and cost of illness in Forteleza (Brazil).

Detailed Description
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Prospective cohort study. The study period initially planned to be two years, is extended by one year to cover one additional dengue season.

Official Title
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An Epidemiological Study to Evaluate the Incidence, Clinical Characteristics and Economic Burden of Dengue in Brazilian Children

Conditions
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Dengue

Intervention / Treatment
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* Other: Data collection
* Procedure: Blood sample collection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female between 5 and 13 years of age (including children at least 5 years of age and excluding children who reached their fourteenth birthday) at the time of enrollment. Written informed consent (and assent when applicable). Subjects who the investigator believes that they and/or their parent(s)/LAR can and will comply with the requirements of the protocol (e.g. willingness to do a hospital visit in case of dengue suspicion, willingness to attend the study hospital return for follow-up visits, able to observe for signs of dengue, understand how to take a temperature, etc). Subjects who plan to attend one of the study schools for two school years following enrollment. Exclusion Criteria: Subjects planning to move from the study area during the two school years following enrollment. Child in care. Enrollment in another study that would conflict with the current study.

Ages Eligible for Study
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Minimum Age: 5 Years
Maximum Age: 13 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Study cohort<br>Children age 5 to 13 years at the time of enrollment, selected from schools in Fortaleza. | Other: Data collection<br>* Socio-demographic information, medical history, yellow fever vaccination history and dengue suspicion data collection.<br>Procedure: Blood sample collection<br>* A blood sample will be collected at each of the three scheduled study visits and any time during the study that dengue is suspected. Samples collected at scheduled visits will be tested for anti-dengue antibodies. Samples collected at visits for dengue suspicion will be tested for dengue diagnosis.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of All Laboratory-confirmed Symptomatic Dengue Infection | Laboratory-confirmed dengue infection refers to suspected symptomatic dengue cases with positive dengue virus identification or serologic evidence of dengue infection through dengue virus identification through Reverse Transcriptase quantitative Polymerase Chain Reaction (RT-qPCR) from first blood sample or anti-dengue Immunoglobulin type M/G (IgM/G) seroconversions between first and second blood sampling. Note: In the study report the denominator for incidence estimation has not been expressed as an absolute number of subjects, but in person-years. Therefore, the category number of subjects analysed has been populated with the number of enrolled subjects attended the study visit after the specified season and in each age stratum. | At Year 1 (2012) | 
| Incidence of All Laboratory-confirmed Symptomatic Dengue Infection | Laboratory-confirmed dengue infection refers to suspected symptomatic dengue cases with positive dengue virus identification or serologic evidence of dengue infection through dengue virus identification through Reverse Transcriptase quantitative Polymerase Chain Reaction (RT-qPCR) from first blood sample or anti-dengue Immunoglobulin type M/G (IgM/G) seroconversions between first and second blood sampling. Note: In the study report the denominator for incidence estimation has not been expressed as an absolute number of subjects, but in person-years. Therefore, the category number of subjects analysed has been populated with the number of enrolled subjects attended the study visit after the specified season and in each age stratum. | At Year 2 (2013) | 
| Incidence of All Laboratory-confirmed Symptomatic Dengue Infection | Laboratory-confirmed dengue infection refers to suspected symptomatic dengue cases with positive dengue virus identification or serologic evidence of dengue infection through dengue virus identification through Reverse Transcriptase quantitative Polymerase Chain Reaction (RT-qPCR) from first blood sample or anti-dengue Immunoglobulin type M/G (IgM/G) seroconversions between first and second blood sampling. Note: In the study report the denominator for incidence estimation has not been expressed as an absolute number of subjects, but in person-years. Therefore, the category number of subjects analysed has been populated with the number of enrolled subjects attended the study visit after the specified season and in each age stratum. | At Year 3 (2014) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of Subjects With Prevalence of Past Dengue Infection (Dengue Seroprevalence) at Enrollment | This outcome measures the occurrence of past dengue infections among subjects who had laboratory results. Proportion was estimated from logistic generalized estimating equations models (GEE) taking the clustering effect of the school into account and was presented per subject enrolment age. Immune response against dengue was assessed via Enzyme-linked Immunosorbent Assay (ELISA). | At Day 0 (At enrollment) | 
| Proportion of Subjects With Primary Asymptomatic Dengue Infection | Asymptomatic dengue primary infection was defined as a documented seroconversion (anti-dengue IgG antibodies) between two sequential sera samples obtained during the scheduled visits, without suspicion of dengue. Proportion of asymptomatic dengue primary infection was analyzed among subjects who had no past dengue infection reported before the beginning of the period. | From Day 0 to Year 3 | 
| Number of Subjects With Laboratory Confirmed or Probable Dengue Cases According Symptomatic Dengue Definition (Primary, Secondary or Unknown) Among the Suspected Dengue Cases | A case of primary or secondary symptomatic dengue infection was defined as laboratory confirmed or probable symptomatic dengue case whose previous sample collected at scheduled Visits 1- 4 (Day 0- Year 3) to detect anti-dengue IgG antibodies was seronegative or seropositive, respectively. A probable dengue case was defined as a suspected symptomatic dengue case with the following laboratory findings: -anti-dengue IgM or anti-dengue IgG positivity in at least one sample (in either blood sample 1 or 2) AND no evidence of viremia (negative dengue virus identification through RT-qPCR) in blood sample 1 AND no evidence of anti-dengue Ig M or IgG seroconversion between blood sample 1 and blood sample 2. | From Year 0 to Year 3 | 
| Incidence of All Laboratory-confirmed or Probable Symptomatic Dengue Infection | Incidence of laboratory confirmed or probable symptomatic dengue infection was assessed by calendar year and age strata. Note: In the study report the denominator for incidence estimation has not been expressed as an absolute number of subjects, but in person-years. Therefore, the category number of subjects analysed has been populated with the number of enrolled subjects attended the study visit after the specified season and in each age stratum. | At Year 1 (2012) | 
| Incidence of All Laboratory-confirmed or Probable Symptomatic Dengue Infection | Incidence of laboratory confirmed or probable symptomatic dengue infection was assessed by calendar year and age strata. Note: In the study report the denominator for incidence estimation has not been expressed as an absolute number of subjects, but in person-years. Therefore, the category number of subjects analysed has been populated with the number of enrolled subjects attended the study visit after the specified season and in each age stratum. | At Year 2 (2013) | 
| Incidence of All Laboratory-confirmed or Probable Symptomatic Dengue Infection | Incidence of laboratory confirmed or probable symptomatic dengue infection was assessed by calendar year and age strata. Note: In the study report the denominator for incidence estimation has not been expressed as an absolute number of subjects, but in person-years. Therefore, the category number of subjects analysed has been populated with the number of enrolled subjects attended the study visit after the specified season and in each age stratum. | At Year 3 (2014) | 
| Number of Dengue Infection Cases by Virus Type (DENV) | Among virus types causing dengue infection were DENV-4 in 2012 and 2013 and DENV-1 in 2014, as assessed by PCR. | From Day 0 to Year 3 | 
| Number of Primary Laboratory Confirmed Symptomatic Dengue Infection Cases | Primary symptomatic dengue infection cases are defined as laboratory confirmed symptomatic dengue cases whose previous sample collected at scheduled visits to detect anti-dengue IgG antibodies were seronegative. Analysis was done by calendar year and age strata. Note: In the study report the denominator for incidence estimation has not been expressed as an absolute number of subjects, but in person-years. Therefore the category number of subjects analysed has been populated with the number of enrolled subjects seronegative for anti-dengue IgG antibodies before the specified season and attended the study visit after the specified season, and in each age stratum. | At Year 1 (2012) | 
| Number of Primary Laboratory Confirmed Symptomatic Dengue Infection Cases | Primary symptomatic dengue infection cases are defined as laboratory confirmed symptomatic dengue cases whose previous sample collected at scheduled visits to detect anti-dengue IgG antibodies were seronegative. Analysis was done by calendar year and age strata. Note: In the study report the denominator for incidence estimation has not been expressed as an absolute number of subjects, but in person-years. Therefore the category number of subjects analysed has been populated with the number of enrolled subjects seronegative for anti-dengue IgG antibodies before the specified season and attended the study visit after the specified season, and in each age stratum. | At Year 2 (2013) | 
| Number of Primary Laboratory Confirmed Symptomatic Dengue Infection Cases | Primary symptomatic dengue infection cases are defined as laboratory confirmed symptomatic dengue cases whose previous sample collected at scheduled visits to detect anti-dengue IgG antibodies were seronegative. Analysis was done by calendar year and age strata. Note: In the study report the denominator for incidence estimation has not been expressed as an absolute number of subjects, but in person-years. Therefore the category number of subjects analysed has been populated with the number of enrolled subjects seronegative for anti-dengue IgG antibodies before the specified season and attended the study visit after the specified season, and in each age stratum. | At Year 3 (2014) | 
| Number of Secondary Laboratory Confirmed Symptomatic Dengue Infection Cases | Secondary symptomatic dengue infection cases are defined as laboratory confirmed symptomatic dengue cases whose previous sample collected at scheduled visits to detect anti-dengue IgG antibodies were seropositive. Note: In the study report the denominator for incidence estimation has not been expressed as an absolute number of subjects, but in person-years. Therefore the category number of subjects analysed has been populated with the number of enrolled subjects seropositive for anti-dengue IgG antibodies before the specified season and attended the study visit after the specified season, and in each age stratum. | At Year 1 (2012) | 
| Number of Secondary Laboratory Confirmed Symptomatic Dengue Infection Cases | Secondary symptomatic dengue infection cases are defined as laboratory confirmed symptomatic dengue cases whose previous sample collected at scheduled visits to detect anti-dengue IgG antibodies were seropositive. Note: In the study report the denominator for incidence estimation has not been expressed as an absolute number of subjects, but in person-years. Therefore the category number of subjects analysed has been populated with the number of enrolled subjects seropositive for anti-dengue IgG antibodies before the specified season and attended the study visit after the specified season, and in each age stratum. | At Year 2 (2013) | 
| Number of Secondary Laboratory Confirmed Symptomatic Dengue Infection Cases | Secondary symptomatic dengue infection cases are defined as laboratory confirmed symptomatic dengue cases whose previous sample collected at scheduled visits to detect anti-dengue IgG antibodies were seropositive. Note: In the study report the denominator for incidence estimation has not been expressed as an absolute number of subjects, but in person-years. Therefore the category number of subjects analysed has been populated with the number of enrolled subjects seropositive for anti-dengue IgG antibodies before the specified season and attended the study visit after the specified season, and in each age stratum. | At Year 3 (2014) | 
| Number of Working Days Missed of Primary Care Giver 1 of Subjects With Laboratory Confirmed Symptomatic Dengue Cases | The number of days off work from caregiver were recorded as part of health economics indirect resource utilization associated with symptomatic dengue infection. | From 21 up to 35 days post laboratory confirmed dengue onset | 
| Number of Working Days Missed of Primary Care Giver 2 of Subjects With Laboratory Confirmed Symptomatic Dengue Cases | The number of days off work from caregiver were recorded as part of health economics indirect resource utilization associated with symptomatic dengue infection. | From 21 up to 35 days post laboratory confirmed dengue onset | 
| Number of Laboratory Confirmed Dengue Infection Cases Associated With Caregiver Absenteeism | The number of laboratory confirmed dengue infections with primary caregivers missing from work was recorded as part of health economics indirect resource utilization associated with symptomatic dengue infection. | From 21 up to 35 days post laboratory confirmed dengue onset | 
| Number of School Days Missed by Subjects | The number of school days missed by subjects due to dengue infection were recorded as part of the dengue active surveillance and indirect resource utilization associated with symptomatic dengue infection. | From 21 up to 35 days post laboratory confirmed dengue onset | 
| Number of Laboratory Confirmed Dengue Infection Cases Associated With Subjects Absenteeism | The number of laboratory confirmed dengue infection cases with subjects missing from school due to dengue infection were recorded as part of the dengue active surveillance and indirect resource utilization associated with symptomatic dengue infection. | From 21 up to 35 days post laboratory confirmed dengue onset | 
| Number of Subjects With Serious Adverse Events (SAEs) | Serious adverse events (SAEs) were collected on the enrolled subjects. SAEs assessed include medical occurrences that result in death, are life threatening, require hospitalization or prolongation of hospitalization or result in disability/incapacity, is a congenital anomaly/birth defect in the offspring of a study subject. | From Day 0 to Year 3 | 
| Number of Symptomatic Dengue Laboratory Confirmed Cases Associated With Hospitalization Direct Medical Resource | Direct medical resource included hospitalization, stay in intensive care units (ICU), medications, diagnostic and therapeutic procedures | From Day 0 to Year 3 | 
| Number of Hospitalization Days Due to Laboratory Confirmed Dengue Cases | Length of hospitalization was part of the direct medical resource, associated with dengue infection. | From Day 0 to Year 3 | 
| Number of Dengue Infection Episodes - Clinical Symptom Since Onset of Suspected Dengue Cases: Temperature | Temperature, expressed in degrees Celsius (°C), was among symptoms of symptomatic dengue infection. | From Day 0 to Year 3 | 
| Number of Dengue Infection Episodes With Any Temperature Interval Since Onset of Suspected Dengue Cases, Among Laboratory Confirmed Dengue Cases | Temperature intervals assessed varied from hypothermia 33.5 to 36.4 degrees Celsius (°C), to normal temperature 36.5-35.9 °C and hyperthermia 37 - 39.9 °C, or were unknown. | From Day 0 to Year 3 | 
| Number of Laboratory Confirmed Dengue Episodes Associated With Clinical Symptoms | Dengue related clinical symptoms included general symptoms, digestive symptoms, respiratory symptoms, hemorrhagic symptoms and any other signs among first symptoms. | From Day 0 to Year 3 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Brazil, Incidence, Dengue virus, Dengue, Dengue infection