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Completed

NCT Number: NCT04448717

COVID-19: Longitudinal Study of Seroprevalence of SARS-CoV-2 Antibodies and Development of Immunity in School Children

There is a lack of knowledge about how many children are infected with SARS-CoV-2, how often they are asymptomatic, and how long the immunity persists.

The main purpose of this study is to measure antibodies to SARS-CoV-2, symptoms, and risk factors in a representative cohort of children and adolescents in the canton of Zurich, Switzerland, shortly after re-opening of the school system and thereafter. The study also investigates antibodies to SARS-CoV-2 in parents of the children and school personnel.

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Key information

Conditions

SARS-CoV 2 COVID-19 Coronaviridae Infections Coronavirus Infections Infections Lung Diseases Nidovirales Infections Pneumonia Pneumonia, Viral RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

5 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Epidemiology, Biostatistics and Prevention Institute (EBPI), University of Zurich

Zurich, 8001, Switzerland

About this study

The role of children and adolescents in the transmission of SARS-CoV-2 remains highly unclear and has been a key question since the early days of the pandemic. It has important consequences for policy decisions, especially concerning the opening of the schools, sport facilities and intergenerational contacts. However, the information on true infection rate and seroprevalence of SARS-CoV-2 is not known in children in Switzerland (and globally), as testing was limited to risk groups and those with SARS-CoV-2 coronavirus disease 2019 (COVID-19) related symptoms. In addition, indications for testing were not uniform and handled heterogeneously. Hence, it is not known whether children are less frequently infected or simply less symptomatic.

This study builds up a system to monitor the seroprevalence of SARS-CoV-2 in children and adolescents who attend school in the canton of Zürich, Switzerland. The investigators aim to assess children of randomly selected primary and secondary schools during the first weeks of re-entering school from all districts of the canton of Zurich in June and July 2020, after the temporary closure due to COVID-19 pandemic, and again in October/November 2020, February/March 2021, November/December 2021, and again in the second half of 2022. The detailed time plan including possible further assessments will be defined depending on the evolution of the pandemic (e.g., 2023). A follow-up capturing health status, symptoms and behaviors over time is important, since it is currently under investigation whether persons may be at risk for reinfection. Thus, a longitudinal assessment is crucial to determine the extent and duration of immunity.

In addition, the seroprevalence of SARS-CoV-2 in the parents of the participating children will be tested in August/September 2020, to examine clusters of infections in households. Seroprevalence of SARS-CoV-2 in school personnel will be tested in August/September 2020 and subsequently in October/November 2020 and February/March 2021, to examine temporal changes in the seroprevalences in the whole school community. Further testing of adults is not planned.

In different subpopulations, further in-depth analysis of immunity markers will be performed in the future.

This study complements the ongoing coordinated efforts of seroprevalence studies in adults in Switzerland, through the Swiss School of Public Health (SSPH+) coordinated CORONA IMMUNITAS studies.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Any school child residing in Switzerland aged 5 years or older and attending a consenting to participate public or private school that hosts classes of interest (grade 1 through 9) in the canton of Zürich.
  • Parents of participating children.
  • Personnel employed in the participating schools.
  • No acute respiratory and SARS-CoV-2 infection:
  • In case of unknown respiratory infection, no presence of symptoms for at least 48 hours.
  • In case of confirmed SARS-CoV-2 infection: inclusion at the earliest 21 days from PCR-positive diagnosis after the onset of potential symptoms and no presence of symptoms for at least 48 hours (according to Standard of Care).
  • Informed consent of parents or legal guardians and children, or the adult participant.

Exclusion criteria

  • No informed consent by schools or children, or the adult participant.
  • Schools with <40 students in one of the sampled grades (1, 2, 4, 5, 7, or 8).
  • Children of Kindergarten age and younger.
  • Suspicion of acute COVID-19 infection.
  • Special need schools.

Treatment and study plan

COVID-19 Antibody testing

Diagnostic Test

COVID-19 Antibody testing in venous blood and/or saliva samples.

Primary outcomes

  1. Seroprevalence of SARS-CoV-2 IgG, IgM and/or IgA antibodies

    Time frame: at inclusion

    Seroprevalence of SARS-CoV-2 IgG, IgM and/or IgA antibodies in randomly selected 5- to 16-year-old population of school-children, their parents, and school personnel, after the peak phase of the first major wave shortly after re-opening of schools in the canton of Zürich, Switzerland.

  2. Seroprevalence of SARS-CoV-2 IgG, IgM and/or IgA antibodies

    Time frame: Month 4-5

    Seroprevalence of SARS-CoV-2 IgG, IgM and/or IgA antibodies in randomly selected 5- to 16-year-old population of school-children and school personnel after 4-5 after recruitement in the canton of Zürich, Switzerland.

  3. Seroprevalence of SARS-CoV-2 IgG, IgM and/or IgA antibodies

    Time frame: Month 8-9

    Seroprevalence of SARS-CoV-2 IgG, IgM and/or IgA antibodies in randomly selected 5- to 16-year-old population of school-children and school personnel after 8-9 months after recruitment in the canton of Zürich, Switzerland.

  4. Seroprevalence of SARS-CoV-2 IgG antibodies

    Time frame: Month 17-18

    Seroprevalence of SARS-CoV-2 IgG antibodies in randomly selected 5- to 16-year-old population of school-children and school personnel after 17-18 months after recruitment in the canton of Zürich, Switzerland.

  5. Seroprevalence of SARS-CoV-2 IgG antibodies

    Time frame: Month 24-30

    Seroprevalence of SARS-CoV-2 IgG antibodies in randomly selected 5- to 16-year-old population of school-children and school personnel after 24-30 months after recruitment in the canton of Zürich, Switzerland.

Secondary outcomes

  1. Presence of self-reported symptoms

    Time frame: at inclusion

    Presence of symptoms (from January 2020) suggestive of a common cold, influenza and similar upper respiratory tract infections prior to the first study visit.

  2. Proportion of seropositive children reporting COVID-19 related symptoms from January 2020

    Time frame: at inclusion

    Proportion of seropositive children reporting symptoms suggestive of a common cold, influenza and similar upper respiratory tract infections between January 2020 and first study visit.

  3. Presence of self-reported symptoms

    Time frame: within 36 months of follow-up

    Presence of symptoms (from January 2020) suggestive of a common cold, influenza and similar upper respiratory tract infections during the follow-up.

  4. Incidence of symptoms in initially seropositive participants

    Time frame: within 36 months of follow-up

    Incidence of self-reported symptoms and SARS-CoV-2 infections after the first study visit in initially seropositive participants.

  5. Proportion of participants, seronegative at inclusion, with symptoms in the follow-up

    Time frame: within 36 months of follow-up

    Proportion of seronegative participants of the first investigation wave who will self-report symptoms and infection with SARS-CoV-2.

  6. Presence of risk factors for infection at inclusion (assessment via custom questionnaire)

    Time frame: at inclusion

    Potential personal (socioeconomic characteristics, health status, presence of infection in family, personal hygiene and social distancing measures) and school-level (implementation of informational, social distancing and hygiene measures at school) risk and preventive factors for SARS-CoV-2 infection prior to the study. Questionnaire includes HBSC and custom questions.

  7. Presence of risk factors for infection during follow-up (assessment via custom questionnaire)

    Time frame: within 36 months of follow-up

    Potential personal (socioeconomic characteristics, health status, presence of infection in family, personal hygiene and social distancing measures) and school-level (implementation of informational, social distancing and hygiene measures at school) risk and preventive factors for SARS-CoV-2 infection during the follow-up. Questionnaire includes HBSC and custom questions.

  8. Self-reported lifestyle changes of participants at inclusion

    Time frame: at inclusion

    Changes in lifestyle during the lock-down, compared to prior to it: frequency and duration (in hours, daily) of physical activity, duration (in hours, daily) of sleep, duration of screen-based media-use (in hours, daily). This outcome is measured only in the children population.

  9. Self-reported lifestyle changes of participants during follow-up

    Time frame: within 36 months of follow-up

    Changes in lifestyle after the lock-down and school reopening, compared to during lock-down: frequency and duration (in hours, daily) of physical activity, duration (in hours, daily) of sleep, duration of screen-based media-use (in hours, daily). This outcome is measured only in the children population.

  10. Self-reported mental well-being (KINDL questionnaire)

    Time frame: within 36 months of follow-up

    Changes over the study time in mental well-being of the participants during and after the lock-down: frequency scale (never/rarely/sometimes/often/always) of self-reported stress, anxiety, self-confidence feelings in the last 7 days. This outcome is measured only in the children population.

  11. Self-reported mental well-being (HBSC questionnaire)

    Time frame: within 36 months of follow-up

    Changes over the study time in mental well-being of the participants during and after the lock-down: frequency scale (daily/weekly/monthly/rarer) of self-reported sadness, anxiety and sleeping problems (HBSC questionnaire question on mental well-being). This outcome is measured only in the children population.

  12. Self-reported quality of life (KINDL questionnaire)

    Time frame: within 36 months of follow-up

    Changes over the study time in quality-of-life of the participants during and after the lock-down: frequency scale (never/rarely/sometimes/often/always) assessment of self-reported positive and negative social interactions with family, friends and in the school environment in the last 7 days. This outcome is measured only in the children population.

  13. Prevalence of seropositive SARS-Cov-2 clusters in schools at inclusion

    Time frame: at inclusion

    Prevalence of clusters of seropositive children, adolescents, and school personnel within schools and classes at baseline.

  14. Incidence of seropositive SARS-Cov-2 clusters in schools during the follow-up

    Time frame: within 36 months of follow-up

    Incidence of clusters of seropositive children, adolescents, and school personnel within schools and classes during the follow-up.

  15. Change in seropositive participants within school or class, depending on the initial proportion of seropositive participants

    Time frame: within 36 months of follow-up

    Impact of the number of children/adolescents and school personnel at a specific period (baseline, at the second and third testing date) within a school or class to the subsequent seropositivity within the same group.

  16. Effect of risk factors and preventive measures on SARS-CoV-2 infection incidence within schools

    Time frame: within 36 months of follow-up

    Incidence of seropositive children and school personnel according to potential risk factors and preventive measures for SARS-CoV-2 infection within schools.

Other outcomes

  1. Evolution of cellular immunity over time

    Time frame: within 36 months of follow-up

    Cellular immunity (T & B cells) in a subsample of previously antibody positive and antibody negative (controls) children.

  2. Long COVID

    Time frame: within 36 months of follow-up

    Self-reported symptoms compatible with Long COVID (i.e., >3months) in seropositive versus seronegative children. Symptoms adapted from International Severe Acute Respiratory and emerging Infection Consortium (ISARIC).

Sponsors and collaborators

Lead sponsor

University of Zurich

Other

Collaborators

  • Swiss School of Public Health (SSPH+)

Registry information

Official study title

Seroprevalence of SARS-CoV-2 Antibodies and Development of Immunity in a Public School Population - a Population-based Observational Study to Inform Policy Making

Acronym: CiaoCorona

Important dates

Study start
2020
Primary completion
2022
Study completion
2022
First posted
Jun 26, 2020
Registry last updated
Apr 3, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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