ClinicalTrials.gg
Status unknownNCT04786353Updated Apr 15, 2024

Long COVID Kids DK - Investigating Long-term Covid-19

An observational study in Covid-19, sponsored by Copenhagen University Hospital, Rigshospitalet. Status unknown at 1 site in Denmark. Per ClinicalTrials.gov, last updated 2024-04-15.

Sponsored by Copenhagen University Hospital, Rigshospitalet · Observational

The sponsor has not verified this record recently (last verified Apr 2024), so the status shown — last known as Active, not recruiting — may be out of date.
Study type
Observational
Model
Cohort
Time perspective
Cross-sectional
Enrollment
330,000
Sex
All
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Study summary

During the COVID-19 pandemic children have been perceived as a group not being especially affected, with less being infected, low symptom burden and low mortality. A small proportion however develop life-threatening hyperinflammation (mis-c) and at least one Danish child has died from this condition. Since the fall of 2020 international awareness has been raised by parents reporting that their children experience gastrointestinal issues, chest pain, headaches, fatigue, joint/muscle pain, sore throat, dizziness, nausea and fever for months following COVID-19 infection.

In this study the investigators aim to investigate the proportions of possible long covid in the 45.000 Danish children that has been tested positive for covid-19. The investigators know from the Danish Covid-19 surveillance data that 300 has been admitted to the hospital within the first 2 weeks after diagnosing. However, no knowledge about how many visits the participants have to the ER and GP compared to children without covid-19 as well as hospital admissions within the first year and medical prescriptions within the first year. This knowledge can give the investigators an indication of how affected these children are on the long term. Furthermore, data has been collected about the long-term symptoms in adults, but not children, and it now seems obvious that this data are needed to fully understand the disease and orchestra the relevant medical attention for children during the covid-19 pandemic.

Read the detailed description

Objectives

WP 1 Objective: to investigate long COVID symptoms after 3,6,9 and 12 months in children tested positive for SARS-CoV-2 compared to children without a positive test.

WP 2 Objective: to describe whether there is a difference in the number of visits to general practitioner, emergency department and hospitalizations in children with and without SARS-CoV-2. In addition, which co-morbid diagnoses are given 3,6,9 and 12 months after diagnosis with COVID and which drugs are prescribed.

Methods

Design: National register study and questionnaire survey.

Outcomes

WP1: Long-term COVID-19 symptoms in children will be identified from questionnaires.

WP2: To determine the difference in number of contacts to the general practitioner, emergency departments and hospitalizations in both children with and without SARS-CoV-2, an identification from COVID-19 data linked with LPR3 and SSR will occur. Identification of co-morbidities will be identified from LPR3 and prescribed drugs are available from LMDB.

Statistical analyses

WP1: To investigate parent and child reported long COVID symptoms numbers and percentages will be presented followed by multiple logistic models offered as odds ratios (OR) with 95% confidence intervals (CI).

WP2: Multiple regressions models presented as OR with 95% CI will be used to examine the differences in contacts regarding the general practitioner, emergency departments, hospitalizations, co-morbidities and prescribed drugs in children with and without COVID.

All analyses will be stratified by age groups and gender.

Population

Exposure: To be identified as an exposure for the current study, children from 0-18 years with at least one positive SARS-CoV-2 test will be identified from COVID-19 data from January 2020 until the last updated version. To be able to identify the parents who will receive the questionnaires the investigators will also need CPR-data on the children's parents.

Non-exposure: Children from 0-18 years without a positive SARS-CoV-2 test for the entire period of January 2020 until the last updated version will be identified from the Danish Civil Registration System. To be able to identify the parents who will receive the questionnaires the investigators will need CPR-data on the parents.

Variables

COVID-19 data will enable information on children with and without positive SARS-CoV-2 tests. The parents who will receive questionnaires will also be identified from this register likewise will data on death, sex and age.

The Temporary Danish National Patient Register (LPR3) will provide data on the number of emergency visits, hospitalizations and co-morbidities.

The Danish Health Insurance Register (SSR) offers numbers of contacts with the general practitioner.

The Danish Medicines Registry (LMDB) enables the investigators to link prescribed drugs.

All registers will be updated monthly by The Danish Health Authorities and the investigators will need data extraction in the period 2020 until the last updated version from all the above-mentioned registers.

Publications of results

All results will be published in international scientist journals as well as the hospital webpage and press releases.

Perspectives

This will be the largest investigation of long COVID in children to date. Denmark has excellent registers and logistics for questionnaires providing a unique opportunity to report on children's health care seeking behavior and symptoms after being infected with COVID-19. Children are an overlooked group during the pandemic and these data will provide essential information for health care staff, politicians and parents.

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Conditions studied

  • Covid-19

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03

In context

COVID-19

7,776 studies on the registry are indexed under COVID-19; 482 are open to participants now.

This study's enrollment of 330,000 is above the median of 260 across 3,188 observational studies indexed under COVID-19.

Browse COVID-19 studies →

Lead sponsor

Copenhagen University Hospital, Rigshospitalet is the lead sponsor of 37 studies on the registry; 12 are open to participants now.

Counted across the registry records on this site, refreshed daily.

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Who can participate

Ages eligible
Child (0–17), Adult (18–64), Older adult (65+)
Sexes eligible
All
Accepts healthy volunteers
No
Sampling method
Non-probability sample

Study population

Exposure: To be identified as an exposure for the current study, children from 0-18 years with at least one positive COVID-19 test will be identified from Covid-19 data from January 2020 until the last updated version. To be able to identify the parents who will receive the questionnaires we will also need CPR-data on the children's parents.

Non-exposure: Children from 0-18 years without a positive COVID-19 test for the entire period of January 2020 until the last updated version will be identified from Covid-19 data. To be able to identify the parents who will receive the questionnaires we will need CPR-data on the parents.

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • must be included in the covid-19 monitoring database

Exclusion criteria

Exclusion Criteria:

-

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Study design

Observational model
Cohort
Time perspective
Cross-sectional
Enrollment
330,000 participants (actual)
Target follow-up
2 Years
Patient registry
Yes

Groups and cohorts

  • COVID positive kids

    Children with at least one positive SARS-CoV-2 test.

    Other: LongCOVIDkidsDK

  • Controls

    Children with no positive SARS-CoV-2 test.

Interventions

  • OtherLongCOVIDkidsDK

    Exposure: To be identified as an exposure for the current study, children from 0-18 years with at least one positive SARS-CoV-2 test will be identified from COVID-19 data from January 2020 until the last updated version. To be able to identify the parents who will receive the questionnaires we will also need CPR-data on the children's parents.

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What researchers measure

Primary outcomes

  1. Contacts to the general practitioner

    To determine the difference in number of contacts to the general practitioner, in children with and without COVID-19, an identification from the Danish COVID-19 database linked with the Danish Health Insurrance Register will occur.

    Time frame: Up to 1 year after diagnosis with covid-19

  2. Hospitalizations

    To determine the number of hospitalizations in children with and without COVID-19, an identification from the Danish COVID-19 database linked with the Danish National Patient Register will occur.

    Time frame: Up to 1 year after diagnosis with covid-19

  3. Diagnoses

    To determine which diagnoses the children with covid-19 are given compared to children without covid-19, an identification from the Danish COVID-19 database linked with the Danish National Patient Register will occur.

    Time frame: Up to 1 year after diagnosis with covid-19

  4. Prescribed drugs

    To determine which drugs the children with COVID-19 are given compared to children without covid-19, an identification from the Danish COVID-19 database linked with the Danish Medicines Registry will occur.

    Time frame: Up to 1 year after diagnosis with covid-19

  5. Long COVID symptoms

    Through self-reported (by child or parent) survey data long COVID symptoms will be evaluated among children with and without COVID-19

    Time frame: Up to 1 year after diagnosis with covid-19

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Study locations

1 site
  • Rigshospitalet, Copenhagen University Hospital
    Copenhagen, Denmark
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References and documents

Publications

  • Berg SK, Wallach-Kildemoes H, Rasmussen LR, Nygaard U, Birk NM, Bundgaard H, Ersboll AK, Thygesen LC, Nielsen SD, Christensen AV. Healthcare use in 12-18-year-old adolescents vaccinated against SARS-CoV-2 versus unvaccinated in a national register-based Danish cohort. Nat Hum Behav. 2025 Apr;9(4):737-745. doi: 10.1038/s41562-024-02097-y. Epub 2025 Jan 20. PubMed 39833423 ↗
  • Bering L, Christensen AV, Birk NM, Thygesen LC, Bundgaard H, Benfield T, Nygaard U, Johannesen J, Nielsen SD, Berg SK. Risk of New-onset Type 1 Diabetes in Danish Children and Adolescents After SARS-CoV-2 Infection: A Nationwide, Matched Cohort Study. Pediatr Infect Dis J. 2023 Nov 1;42(11):999-1001. doi: 10.1097/INF.0000000000004063. Epub 2023 Aug 3. PubMed 37566892 ↗
  • Kikkenborg Berg S, Palm P, Nygaard U, Bundgaard H, Petersen MNS, Rosenkilde S, Thorsted AB, Ersboll AK, Thygesen LC, Nielsen SD, Vinggaard Christensen A. Long COVID symptoms in SARS-CoV-2-positive children aged 0-14 years and matched controls in Denmark (LongCOVIDKidsDK): a national, cross-sectional study. Lancet Child Adolesc Health. 2022 Sep;6(9):614-623. doi: 10.1016/S2352-4642(22)00154-7. Epub 2022 Jun 23. PubMed 35752194 ↗
  • Kikkenborg Berg S, Dam Nielsen S, Nygaard U, Bundgaard H, Palm P, Rotvig C, Vinggaard Christensen A. Long COVID symptoms in SARS-CoV-2-positive adolescents and matched controls (LongCOVIDKidsDK): a national, cross-sectional study. Lancet Child Adolesc Health. 2022 Apr;6(4):240-248. doi: 10.1016/S2352-4642(22)00004-9. Epub 2022 Feb 8. PubMed 35143771 ↗

Individual participant data

Plan to share: No

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reached

Started Jul 2021 (actual). Primary completion is estimated for Jun 2024, 35 months after the start.

How these figures are worked out, and which studies are left out of them.

Registered
Mar 1, 2021
First posted
Mar 8, 2021
StartActual
Jul 1, 2021
Primary completionEst.
Jun 2024
CompletionEst.
Jun 2024
Last update
Apr 15, 2024
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Apr 15, 2024, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT04786353
Lead sponsor
Copenhagen University Hospital, Rigshospitalet
Responsible party
Selina Kikkenborg Berg (Professor, Copenhagen University Hospital, Rigshospitalet) — Principal investigator
First posted
Mar 8, 2021
Start date
Jul 1, 2021
Primary completion
Jun 2024 (estimated)
Completion
Jun 2024 (estimated)
Last update
Apr 15, 2024

Study contacts

Selina K Berg, PhD
principal investigator · 29190623

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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This study is status unknown, as verified in Apr 2024. You cannot join it, but the record below documents what was studied.

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