Covid-19NCT04786353
Long COVID Kids DK - Investigating Long-term Covid-19
An observational study of Covid-19, run by Copenhagen University Hospital, Rigshospitalet at 1 site in Denmark.
Trial 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. Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- Covid-19
- What is being tested?
- LongCOVIDkidsDK
- How many people
- 330,000 participants
- Where
- 1 siteDenmark
- Study dates
- 1 Jul 2021to Jun 2024
- How long will I take part?
- 2 Years
- 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 Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
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.
Who may be able to join
- must be included in the covid-19 monitoring database
Who cannot join
- -
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Long COVID Kids DK - Investigating Long-term Hospitalizations, GP Visits, Co-morbidities, Drug Prescriptions and Symptoms in Danish Children With Covid-19
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.
- Conditions
- Covid-19
- Being tested
- LongCOVIDkidsDK
- Medical subject headings
- COVID-19
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
LongCOVIDkidsDKOther
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.
| Study group | Role | What they receive |
|---|---|---|
| COVID positive kids | Children with at least one positive SARS-CoV-2 test. Receives: Other: LongCOVIDkidsDK | |
| Controls | Children with no positive SARS-CoV-2 test. |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: Up to 1 year after diagnosis with covid-19
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.
Measured: Up to 1 year after diagnosis with covid-19
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.
Measured: Up to 1 year after diagnosis with covid-19
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.
Measured: Up to 1 year after diagnosis with covid-19
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
Measured: Up to 1 year after diagnosis with covid-19
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Mar 2021
- Study start1 Jul 2021
- Primary completionJun 2024 (estimated)
- Study completionJun 2024 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Covid-19Studies of the same condition, open and under way.
- More trials run by Copenhagen University Hospital, RigshospitaletThe 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
- Cross-sectional
- Enrolment
- 330,000 participants (actual)
- Target duration
- 2 Years
Sponsor and investigators
- Lead sponsor
- Copenhagen University Hospital, Rigshospitalet
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Selina Kikkenborg Berg, Copenhagen University Hospital, Rigshospitalet
- Investigators
- Selina K Berg, PhD, Principal investigator, 29190623
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04786353
- Sponsor's protocol ID
- Long COVID-19 Kids DK
- Status last verified
- Apr 2024
- First submitted
- 1 Mar 2021
- Last updated
- 15 Apr 2024
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
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 39833423Bering 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 37566892Kikkenborg 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 35752194Kikkenborg 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
Study at a glance
From the registry record, last updated by the sponsor on 15 Apr 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Long COVID Kids DK - Investigating Long-term Hospitalizations, GP Visits, Co-morbidities, Drug Prescriptions and Symptoms in Danish Children With Covid-19
- ClinicalTrials.gov ID
- NCT04786353
- Acronym / sponsor ID
- Long COVID-19 Kids DK
- Conditions
- Covid-19
- Study type
- Observational
- Recruitment status
- Unknown status
- Enrolment
- 330,000 participants (actual)
- Lead sponsor
- Copenhagen University Hospital, RigshospitaletUniversity, hospital or other
- Study start
- 1 Jul 2021 (actual)
- Primary completion
- Jun 2024 (estimated)
- Study completion
- Jun 2024 (estimated)
- First posted
- 8 Mar 2021 (actual)
- 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.
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.
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.
Study design
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Target follow-up
- 2 Years
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| COVID positive kids | – | Other: LongCOVIDkidsDKChildren with at least one positive SARS-CoV-2 test. |
| Controls | – | –Children with no positive SARS-CoV-2 test. |
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- 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.
Key inclusion criteria (1 listed)
- must be included in the covid-19 monitoring database
Key exclusion criteria (1 listed)
- -
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 |
|---|---|---|
| LongCOVIDkidsDKExposure: 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. | Other | COVID positive kids |
Primary outcome
Contacts to the general practitioner
Time frame: Up to 1 year after diagnosis with covid-19
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.
Hospitalizations
Time frame: Up to 1 year after diagnosis with covid-19
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.
Diagnoses
Time frame: Up to 1 year after diagnosis with covid-19
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.
Prescribed drugs
Time frame: Up to 1 year after diagnosis with covid-19
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.
Long COVID symptoms
Time frame: Up to 1 year after diagnosis with covid-19
Through self-reported (by child or parent) survey data long COVID symptoms will be evaluated among children with and without COVID-19
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Apr 2024.
- Derived from this study: PubMed 39833423Berg 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.
- Derived from this study: PubMed 37566892Bering 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.
- Derived from this study: PubMed 35752194Kikkenborg 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.
- Derived from this study: PubMed 35143771Kikkenborg 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.
- Individual participant dataSharing planned: No
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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.
Selina K Berg, PhD principal investigator
29190623
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 Covid-19, run by Copenhagen University Hospital, Rigshospitalet at 1 site in Denmark.
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 1 inclusion and 1 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: status not confirmed, as of the sponsor's last update on 15 Apr 2024. 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 Denmark. 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?
Results are not available in the source record.
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?
Contacts to the general practitioner (time frame: Up to 1 year after diagnosis with covid-19). The study lists 5 primary outcomes in all. 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 NCT04786353, which also lists 4 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 15 Apr 2024.