SARS-CoV 2NCT04853004
Current and Past SARS-CoV-2 Infection and COVID-19 in Healthcare With Regard to Vaccinations
An observational study of SARS-CoV 2, run by Karolinska Institutet at 1 site in Sweden.
Trial summary
To investigate the incidence of SARS-CoV-2 infections after vaccination, to monitor the development of SARS-CoV-2 antibody levels after vaccination and to compare this in relation to both previous health \& disease, previous antibody responses and in relation to future disease occurring after vaccination. Read more about this study
- Who is it for?
- Ages 18 to 99 years
- Conditions the study is for
- SARS-CoV 2
- What is being tested?
- SARS-CoV2 antibody measurement
- Type of treatment
- Vaccines
- How many people
- 10,000 participants
- Where
- 1 siteSweden
- Study dates
- 1 Apr 2021to 31 Dec 2025
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
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 to 99 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: -Personnel within healthcare in Stockholm County who have previously participated in a study on SARS-CoV-2 infection within healthcare in Stockholm County and who are offered a vaccine against Covid-19.
Who may be able to join
- Study participant who agreed to be included in the study "Studies of ongoing and completed SARS-CoV-2 infection (which causes COVID-19) within the healthcare in Stockholm County".
- Study participant who has received or will receive vaccine against Covid-19 and who gives new written consent to the study "Studies of ongoing and completed SARS-CoV-2 infection (which causes COVID-19) within the healthcare in Stockholm County, with regard to vaccinations".
Who cannot join
- those who have not given informed consent to participate in the study In this study, no initiative is taken for vaccination. The vaccinations are carried out by the healthcare system and of course follow the established exclusion and inclusion criteria for the approved vaccines. All persons who have received the vaccine and who give written consent are eligible to be included in the study.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Studies of Ongoing and Completed SARS-CoV-2 Infection (Which Causes COVID-19) Within the Healthcare in Stockholm County, With Regard to Vaccinations.
To investigate the incidence of SARS-CoV-2 infections after vaccination, to monitor the development of SARS-CoV-2 antibody levels after vaccination and to compare this in relation to both previous health \& disease, previous antibody responses and in relation to future disease occurring after vaccination.
Read the detailed description
The purpose of the study is to analyze the effect of and possible side effects of SARS-CoV2 vaccinations in the cohort study where data on sick leave, SARS-Cov2 infections and SARS-CoV2 antibody levels are well documented even before vaccination.
The main outcome measures are the presence of SARS-CoV-2 (ongoing infection) and the presence of antibodies to SARS-CoV-2.
For the vaccination effect, the factors that are primarily associated with protection against infection are analyzed, such as age, sex, workplace, antibody response to SARS-CoV-2 and vaccination date.
The analyzes are planned to be performed with multivariate logistic regression with Relative Risk as the outcome measure.
Data from the analysis of virus antibodies are planned to be performed divided into whether low, medium or high levels of antibodies occur, with the same analysis for possible association with the factors listed above.
- Conditions
- SARS-CoV 2
- Being tested
- SARS-CoV2 antibody measurement
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SARS-CoV2 antibody measurementDiagnostic test
Blood samples for serology, collected immediately prior to and five to ten weeks after vaccination against SARS-CoV2, to be analyzed for the presence of SARS-CoV-2 antibodies.
| Study group | Role | What they receive |
|---|---|---|
| Study cohort | Personnel in health and care in Stockholm County, who have previously participated in a study where data on sick leave, SARS-Cov2 infections and SARS-CoV2 antibody levels were collected and documented form the study cohort. Receives: Diagnostic Test: SARS-CoV2 antibody measurement |
What is being measured
The primary outcome is the main question the study is designed to answer.
SARS-CoV-2 infection
Characterized by whether they are asymptomatic infections or sick leave-requiring infections.
Measured: 24 months post primary vaccination
Secondary outcomes (1)
SARS-CoV-2 antibody induction
Antibodies will be characterized in terms of antibody levels, which SARS-CoV-2 antigen to which the response is directed and whether the antibodies are protective or not.
Measured: 24 months post primary vaccination
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Apr 2021
- Study start1 Apr 2021
- Primary completion31 Mar 2023
- Study completion31 Dec 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for SARS-CoV 2Studies of the same condition, open and under way.
- More trials run by Karolinska InstitutetThe 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
- 10,000 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Karolinska Institutet
- Sponsor type
- University, hospital or other
- Collaborators
- Karolinska University Hospital
- Responsible party
- Principal investigator, Joakim Dillner, Karolinska Institutet
- Investigators
- Joakim Dillner, MD, PhD, Principal investigator, Karolinska Institutet
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04853004
- Sponsor's protocol ID
- Covid19_7
- Status last verified
- Mar 2025
- First submitted
- 19 Apr 2021
- Last updated
- 20 Mar 2025
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: We have yet to determine whether the IPD will be available for other researchers.
Study at a glance
From the registry record, last updated by the sponsor on 20 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Studies of Ongoing and Completed SARS-CoV-2 Infection (Which Causes COVID-19) Within the Healthcare in Stockholm County, With Regard to Vaccinations.
- ClinicalTrials.gov ID
- NCT04853004
- Acronym / sponsor ID
- Covid19_7
- Conditions
- SARS-CoV 2
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 10,000 participants (estimated)
- Lead sponsor
- Karolinska InstitutetUniversity, hospital or other
- Collaborators
- Karolinska University Hospital
- Study start
- 1 Apr 2021 (actual)
- Primary completion
- 31 Mar 2023 (actual)
- Study completion
- 31 Dec 2025 (estimated)
- First posted
- 21 Apr 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.
To investigate the incidence of SARS-CoV-2 infections after vaccination, to monitor the development of SARS-CoV-2 antibody levels after vaccination and to compare this in relation to both previous health \& disease, previous antibody responses and in relation to future disease occurring after vaccination.
Detailed description
The purpose of the study is to analyze the effect of and possible side effects of SARS-CoV2 vaccinations in the cohort study where data on sick leave, SARS-Cov2 infections and SARS-CoV2 antibody levels are well documented even before vaccination.
The main outcome measures are the presence of SARS-CoV-2 (ongoing infection) and the presence of antibodies to SARS-CoV-2.
For the vaccination effect, the factors that are primarily associated with protection against infection are analyzed, such as age, sex, workplace, antibody response to SARS-CoV-2 and vaccination date.
The analyzes are planned to be performed with multivariate logistic regression with Relative Risk as the outcome measure.
Data from the analysis of virus antibodies are planned to be performed divided into whether low, medium or high levels of antibodies occur, with the same analysis for possible association with the factors listed above.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Study cohort | – | Diagnostic Test: SARS-CoV2 antibody measurementPersonnel in health and care in Stockholm County, who have previously participated in a study where data on sick leave, SARS-Cov2 infections and SARS-CoV2 antibody levels were collected and documented form the study cohort. |
Who may qualify
- Ages
- 18 to 99 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- -Personnel within healthcare in Stockholm County who have previously participated in a study on SARS-CoV-2 infection within healthcare in Stockholm County and who are offered a vaccine against Covid-19.
Key inclusion criteria (2 listed)
- Study participant who agreed to be included in the study "Studies of ongoing and completed SARS-CoV-2 infection (which causes COVID-19) within the healthcare in Stockholm County".
- Study participant who has received or will receive vaccine against Covid-19 and who gives new written consent to the study "Studies of ongoing and completed SARS-CoV-2 infection (which causes COVID-19) within the healthcare in Stockholm County, with regard to vaccinations".
Key exclusion criteria (1 listed)
- those who have not given informed consent to participate in the study In this study, no initiative is taken for vaccination. The vaccinations are carried out by the healthcare system and of course follow the established exclusion and inclusion criteria for the approved vaccines. All persons who have received the vaccine and who give written consent are eligible to be included in the study.
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 |
|---|---|---|
| SARS-CoV2 antibody measurementBlood samples for serology, collected immediately prior to and five to ten weeks after vaccination against SARS-CoV2, to be analyzed for the presence of SARS-CoV-2 antibodies. | Diagnostic test | Study cohort |
Primary outcome
SARS-CoV-2 infection
Time frame: 24 months post primary vaccination
Characterized by whether they are asymptomatic infections or sick leave-requiring infections.
1 secondary outcome
SARS-CoV-2 antibody induction
Time frame: 24 months post primary vaccination
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Mar 2025.
- Individual participant dataSharing planned: Undecided. We have yet to determine whether the IPD will be available for other researchers.
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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.
Joakim Dillner, MD, PhD principal investigator
Karolinska Institutet
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 SARS-CoV 2, run by Karolinska Institutet at 1 site in Sweden.
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 2 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: under way, not looking for participants, as of the sponsor's last update on 20 Mar 2025. 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 Sweden. 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?
This study is still under way. Results are not available in the source record yet.
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?
SARS-CoV-2 infection (time frame: 24 months post primary vaccination). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 20 Mar 2025.