COVID-19NCT05534009
Health Care Workers Cohort Study in the EuCARE Project (EuCARE-HCW)
An observational study of COVID-19, run by Euresist Network GEIE at 7 sites in 6 countries.
Trial summary
The WP3 healthcare workers cohort in EuCARE is an observational multicentre study including collection of retrospective (historical) and prospective data and sample collection from health care workers with either a vaccination or a confirmed SARS-CoV-2 infection. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- COVID-19
- What is being tested?
- Follow up of the first known immunization event
- Type of treatment
- Vaccines
- How many people
- 1,800 participants
- Where
- 7 sitesin 6 countries
- Study dates
- 1 Apr 2022to 15 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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: For each subject baseline will be the occurrence of the first known immunization event, either natural infection or vaccination. The follow-up is planned to last 24 months with respect to this baseline. Health CareWorkers can be enrolled in the category of: (i) vaccination not followed by any later infection, (ii) infection followed by vaccination and (iii) vaccination followed by infection. However, infections diagnosed during the first wave of the epidemic are suitable for the analysis of natural immunity to SARS-CoV-2 because vaccination was administered several months later.
Who may be able to join
- The study subjects will be selected based on the following inclusion criteria:
- Adult (>18 years) HCW with mandatory information on their SARS-CoV-2 infection and vaccination status.
- For those with a history of SARS-CoV-2 infection, diagnosis obtained by detection of SARS-CoV-2 RNA
- Having a signed informed consent when required by ethical approval
Who cannot join
None listed.
Trial locations and contacts
7 sites in 6 countries. Contact the study team or a site near you to ask about taking part.
7 sites in 6 countries
Italy2 sites, 2 recruiting
- Recruiting
Azienda Socio-Sanitaria Territoriale Santi Paolo e Carlo
Milan
ANTONELLA D'ARMINIO MONFORTE, PROF, +390281843045-6, antonella.darminio@unimi.it
- Recruiting
Ieo Istituto Europeo Di Oncologia
Milan
SARA GANDINI, DR, sara.gandini@ieo.it
Germany1 site, 1 recruiting
- Recruiting
Heinrich Heine university
Düsseldorf
Bjoern Erik Jensen, DR, Bjoern-ErikOle.Jensen@med.uni-duesseldorf.de
Lithuania1 site, 1 recruiting
- Recruiting
Viesoji Istaiga Vilniaus Uiversiteto Ligoninė Santaros klinikos
Vilnius
DANIEL Naumovas, DR, Daniel.Naumovas@santa.lt
Mexico1 site, 1 recruiting
- Recruiting
Hospital Juan Ghaham Casasus
Villahermosa
Gibran Rubio Quintanares, DR, +49 6103 77 2125, Gibran.Rubio@pei.de
Portugal1 site, 1 recruiting
- Recruiting
Centro Hospitalar de Lisboa Ocidental
Lisbon
CRISTINA TOSCANO, MD, +351 210432541, ctoscano@chlo.min-saude.pt
Vietnam1 site, 1 recruiting
- Recruiting
Bach Mai Hospital
Hanoi
CUONG DO DUY, MD, doduy.cuong@bachmai.edu.vn
About this study
The WP3 healthcare workers cohort in EuCARE is an observational multicentre study including collection of retrospective (historical) and prospective data and sample collection from health care workers with either a vaccination or a confirmed SARS-CoV-2 infection. Samples from HCW are sent to central laboratories for WP2 study were the impact of different variants in humoral and cellular immunity is to be analysed by biostatistical methods and with artificial intelligence in WP5. This analysis will focus on the impact on vaccine escape of viral variants / viral sequences as well as on any escape from any combination of natural and vaccine induced immunity. Eight countries will participate (Portugal, Italy, Germany, Lithuania, Georgia, Russia, Vietnam and Mexico).
Read the detailed description
Background: Protection from SARS-CoV-2 infection is known to occur soon after vaccination or natural disease, fading over time. Although protection from serious illness does occur, protection from infection is insufficient and the impact of each variant and of each vaccine or vaccine schedule is a matter of continuous study. Recruiting participants from countries with different vaccines and vaccine schedules is of upmost importance to analyse these relationships and breakthrough infections. Study objectives: The EuCARE-HCW study contributes with data and samples from
HCW to EuCARE-IMMUNITY study that will analyse the NtAb and CMI to different SARS- CoV-2 variants following any combination of natural infection and vaccination. Specific
objectives include:
- to collect data and biological material from COVID-19 healthcare workers in 9 clinics from 8 countries and 3 continents.
- Enrolment of HCW with an immunogenic event, either vaccination or infection.
- Periodic collection of serum and whole blood every 4 months since enrolment and during 12-24 months (depending on how long immunity persists).
- Sample preparation, storage and shipment to central EuCARE laboratories where WP2 study group will analyse natural and artificial immunity to SARS-CoV-2 variants (EuCARE-IMMUNITY), namely:
- Analyse the magnitude, breadth and duration of immunity following natural infection and/or vaccination.
- Define the cross-immunity among the different viral variants.
- Analyse the immune escape in a comprehensive set of combinations of vaccines and natural infection(s).
- To accomplish the above objectives, WP2 will test:
- Neutralising antibodies
- Cellular immunity
- Viral sequences
- Conditions
- COVID-19
- Being tested
- Follow up of the first known immunization event
- Medical subject headings
- COVID-19
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Follow up of the first known immunization eventOther
The baseline for enrolment into the study is defined by the occurrence of the first known immunization event, either natural infection or vaccination. The follow-up is planned to last 24 months with respect to this baseline. In subjects with natural infection, the viral variant must be determined for each prospective case by analysis of a nasopharyngeal swab obtained as soon as possible at diagnosis. For historical cases where the variant was not determined and a contemporary nasopharyngeal swab has not been stored, the viral variant may be inferred when a specific variant was dominating the geographic area according to official records available at local health agencies. However, the variant assignment will be labelled as putative, rather than proved.
HCWs can be enrolled in the category of:
(i) vaccination not followed by any later infection, (ii) infection followed by vaccination and (iii) vaccination followed by infection.
| Study group | Role | What they receive |
|---|---|---|
| Heath care workers (HCW) | Adult (>18 years) HCW with mandatory information on their SARS-CoV-2 infection and vaccination status. For those with a history of SARS-CoV-2 infection, diagnosis obtained by detection of SARS-CoV-2 RNA Receives: Other: Follow up of the first known immunization event |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of HCW involved in the study
To collect the higher possible number of data and biological materials from the HCWs of the participating Units
Measured: through study completion, an average of 3 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Sep 2022
- Study start1 Apr 2022
- Primary completion15 Dec 2025 (estimated)
- Study completion15 Dec 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for COVID-19Studies of the same condition, open and under way.
- 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
- Other
- Enrolment
- 1,800 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Euresist Network GEIE
- Sponsor type
- University, hospital or other
- Collaborators
- Centro Hospitalar Lisboa Ocidental, ASST Santi Paolo e Carlo, Bach Mai Hospital, Hospital Regional de Alta Especialidad "Dr. Juan Graham Casasus", Heinrich-Heine University, Duesseldorf, Istituto Europeo di Oncologia, Vilnius University Hospital Santaros Klinikos
- Responsible party
- Sponsor
- Investigators
- CRISTINA TOSCANO, DR, Study chair, Centro Hospitalar de Lisboa Ocidental (CHLO)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05534009
- Sponsor's protocol ID
- EuCARE-HCW
- Status last verified
- Aug 2025
- First submitted
- 6 Sep 2022
- Last updated
- 19 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: The study is part of a project funded by the European Commission and the project agreement with theCommission affirms that the data and the results will be publi
Study at a glance
From the registry record, last updated by the sponsor on 19 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Health Care Workers Cohort Study in the EuCARE Project (EuCARE-HCW)
- ClinicalTrials.gov ID
- NCT05534009
- Acronym / sponsor ID
- EuCARE-HCW
- Conditions
- COVID-19
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 1,800 participants (estimated)
- Lead sponsor
- Euresist Network GEIEUniversity, hospital or other
- Collaborators
- Centro Hospitalar Lisboa Ocidental, ASST Santi Paolo e Carlo, Bach Mai Hospital, Hospital Regional de Alta Especialidad "Dr. Juan Graham Casasus", Heinrich-Heine University, Duesseldorf, Istituto Europeo di Oncologia, Vilnius University Hospital Santaros Klinikos
- Study start
- 1 Apr 2022 (actual)
- Primary completion
- 15 Dec 2025 (estimated)
- Study completion
- 15 Dec 2025 (estimated)
- First posted
- 9 Sep 2022 (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.
The WP3 healthcare workers cohort in EuCARE is an observational multicentre study including collection of retrospective (historical) and prospective data and sample collection from health care workers with either a vaccination or a confirmed SARS-CoV-2 infection. Samples from HCW are sent to central laboratories for WP2 study were the impact of different variants in humoral and cellular immunity is to be analysed by biostatistical methods and with artificial intelligence in WP5. This analysis will focus on the impact on vaccine escape of viral variants / viral sequences as well as on any escape from any combination of natural and vaccine induced immunity. Eight countries will participate (Portugal, Italy, Germany, Lithuania, Georgia, Russia, Vietnam and Mexico).
Detailed description
Background: Protection from SARS-CoV-2 infection is known to occur soon after vaccination or natural disease, fading over time. Although protection from serious illness does occur, protection from infection is insufficient and the impact of each variant and of each vaccine or vaccine schedule is a matter of continuous study. Recruiting participants from countries with different vaccines and vaccine schedules is of upmost importance to analyse these relationships and breakthrough infections. Study objectives: The EuCARE-HCW study contributes with data and samples from
HCW to EuCARE-IMMUNITY study that will analyse the NtAb and CMI to different SARS- CoV-2 variants following any combination of natural infection and vaccination. Specific
objectives include:
- to collect data and biological material from COVID-19 healthcare workers in 9 clinics from 8 countries and 3 continents.
- Enrolment of HCW with an immunogenic event, either vaccination or infection.
- Periodic collection of serum and whole blood every 4 months since enrolment and during 12-24 months (depending on how long immunity persists).
- Sample preparation, storage and shipment to central EuCARE laboratories where WP2 study group will analyse natural and artificial immunity to SARS-CoV-2 variants (EuCARE-IMMUNITY), namely:
- Analyse the magnitude, breadth and duration of immunity following natural infection and/or vaccination.
- Define the cross-immunity among the different viral variants.
- Analyse the immune escape in a comprehensive set of combinations of vaccines and natural infection(s).
- To accomplish the above objectives, WP2 will test:
- Neutralising antibodies
- Cellular immunity
- Viral sequences
Study design
- Observational model
- Cohort
- Time perspective
- Other
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Heath care workers (HCW) | – | Other: Follow up of the first known immunization eventAdult (>18 years) HCW with mandatory information on their SARS-CoV-2 infection and vaccination status. For those with a history of SARS-CoV-2 infection, diagnosis obtained by detection of SARS-CoV-2 RNA |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- For each subject baseline will be the occurrence of the first known immunization event, either natural infection or vaccination. The follow-up is planned to last 24 months with respect to this baseline. Health CareWorkers can be enrolled in the category of: (i) vaccination not followed by any later infection, (ii) infection followed by vaccination and (iii) vaccination followed by infection. However, infections diagnosed during the first wave of the epidemic are suitable for the analysis of natural immunity to SARS-CoV-2 because vaccination was administered several months later.
Key inclusion criteria (4 listed)
- Adult (>18 years) HCW with mandatory information on their SARS-CoV-2 infection and vaccination status.
- For those with a history of SARS-CoV-2 infection, diagnosis obtained by detection of SARS-CoV-2 RNA
- Having a signed informed consent when required by ethical approval
Key exclusion criteria (0 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 |
|---|---|---|
| Follow up of the first known immunization eventThe baseline for enrolment into the study is defined by the occurrence of the first known immunization event, either natural infection or vaccination. The follow-up is planned to last 24 months with respect to this baseline. In subjects with natural infection, the viral variant must be determined for each prospective case by analysis of a nasopharyngeal swab obtained as soon as possible at diagnosis. For historical cases where the variant was not determined and a contemporary nasopharyngeal swab has not been stored, the viral variant may be inferred when a specific variant was dominating the geographic area according to official records available at local health agencies. However, the variant assignment will be labelled as putative, rather than proved. HCWs can be enrolled in the category of: (i) vaccination not followed by any later infection, (ii) infection followed by vaccination and (iii) vaccination followed by infection. | Other | Heath care workers (HCW) |
Primary outcome
Number of HCW involved in the study
Time frame: through study completion, an average of 3 years
To collect the higher possible number of data and biological materials from the HCWs of the participating Units
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 19 Sep 2025.
- Individual participant dataSharing planned: Yes. The study is part of a project funded by the European Commission and the project agreement with theCommission affirms that the data and the results will be publi
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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.
CRISTINA TOSCANO, DR study chair
Centro Hospitalar de Lisboa Ocidental (CHLO)
7 sites in 6 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of COVID-19, run by Euresist Network GEIE at 7 sites in 6 countries.
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 4 inclusion and 0 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: looking for participants now, as of the sponsor's last update on 19 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 7 sites in Italy, Germany, Lithuania, Mexico, Portugal and 1 more country. 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?
Contact FRANCESCA INCARDONA, DR (+393356112830, francesca.incardona@euresist.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of HCW involved in the study (time frame: through study completion, an average of 3 years). 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 19 Sep 2025.