SARS-COV-2 Seroprevalence and Seroconversion Among Employees of the UZ Brussel Following COVID-19 Vaccination Using an Adenoviral Vector

NCT04939402 | Active Not Recruiting

• 1 other identifier: COVEMUZ-3
• Study Type: interventional
• Target: 200
• Locations: 1 country
• Sites: 1

Brief Summary

A novel zoonotic coronavirus was discovered in Wuhan (Hubei Province, China) mid-December 2019 and was named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The virus rapidly spread to the rest of the world, including Europe and explicitly affects the respiratory system, generating Coronavirus disease 2019 (COVID-19). Employees of the university hospital of Brussels (UZ Brussel) presenting symptoms suggestive of COVID-19 are offered to be tested with real-time PCR on nasopharyngeal swabs. As asymptomatic infections have been described and as the PCR can be negative when taken late after onset of symptoms, serologic tests can be performed. The SARS-CoV 2003 epidemic demonstrated that serological assays were a useful diagnostic tool of non-acute infections. Although it is still uncertain whether convalescing patients have a risk of re-infection, recent data suggest that SARS-CoV-2 antibodies could protect at least for some time from subsequent viral exposures. As the COVID-19 pandemic had devastating medical, economic and social consequences, safe and effective prophylactic vaccines were urgently needed. And thus several candidate vaccines against SARS-CoV-2 have been developed. The vaccination campaign of the health care workers of the UZ Brussel started mid January 2021. The first available vaccine was the BNT162b2 (Pfizer) vaccine. Early March 2021, in order to accelerate the vaccination of the UZ Brussel employees, the ChAdOx1 nCoV-19 (AZD12222) (Oxford, AstaZeneca) vaccination program was implemented in parallel with the BNT162b2 vaccination program In the COVEMUZ-2 study the investigators have already started to document the SARS-CoV-2 seroprevalence and seroconversion among vaccinated employees (using BNT162b2) in the UZ Brussels. In this study, the investigators aim to prospectively document the SARS-CoV-2 seroprevalence and seroconversion among vaccinated employees (using ChAdOx1 nCoV-19) of the UZ Brussel, at three different time points, namely 6 weeks (+/- 2 weeks; T1), 6 months (+/- 1 month; T2) and 12 months (+/- 1 month; T3) after the second vaccination.

Conditions

SARS-CoV-2; Covid19

Outcome Measures

Primary Outcomes (2)

• Seroprevalence

  To document SARS-CoV-2 seroprevalence among employees of the UZ Brussel after ChAdOx1 nCoV-19 vaccination for SARS-CoV-2, at 8 (+/- 2) weeks after the first vaccination (T1); and 6 and 12 months after the first vaccination (T2 and T3) using a validated immuno-assay for detection of SARS-CoV-2 IgG antibodies

  Change from baseline to 8 weeks, 6 months and 12 months timepoint

• Seroconversion

  To document SARS-CoV-2 seroconversion among employees of the UZ Brussel after ChAdOx1 nCoV-19 vaccination for SARS-CoV-2, at 8 (+/- 2) weeks after the first vaccination (T1); and 6 and 12 months after the first vaccination (T2 and T3) using a validated immuno-assay for detection of SARS-CoV-2 IgG antibodies

  Change from baseline to 8 weeks, 6 months and 12 months timepoint

Secondary Outcomes (6)

• SARS-CoV-2 seroprevalence before and after vaccination

  Change from baseline to 8 weeks, 6 months and 12 months timepoint

• incidence of new definite cases

  Change from baseline to 8 weeks, 6 months and 12 months timepoint

• incidence of new probable cases

  Change from baseline to 8 weeks, 6 months and 12 months timepoint

• antibody kinetics of the SARS-CoV-2 specific antibodies using immunassays

  Change from baseline to 8 weeks, 6 months and 12 months timepoint

• antigen-specificity of the SARS-CoV-2-specific T cells

  Change from baseline to 8 weeks, 6 months and 12 months timepoint

Study Arms (1)

General

OTHER

All patients follow this arm. Patients will undergo 3 blood sample testings at 3 different time points and have to fill in a questionnaire at 3 different time points

Diagnostic Test: Serological testing

Interventions

Serological testing DIAGNOSTIC_TEST

Antibody testing for Sars-CoV-2 specific antibodies in blood + T cell immunity

General

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Any adult employee of the UZ Brussel at T1 who has been vaccinated at the UZ Brussel with ChAdOx1 nCoV-19 vaccine between the 2nd of March and the 9th of March 2021 after participating to phase 4 of the COVEMUZ study between the 25th of January and the 12th of February and has provided a signed informed consent.

Sponsors & Collaborators

• Universitair Ziekenhuis Brussel: lead

Study Sites (1)

UZ Brussel

Brussels, 1090, Belgium

Location

MeSH Terms

Conditions

COVID-19

Interventions

COVID-19 Serological Testing

Condition Hierarchy (Ancestors)

Pneumonia, Viral; Pneumonia; Respiratory Tract Infections; Infections; Virus Diseases; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; RNA Virus Infections; Lung Diseases; Respiratory Tract Diseases

Intervention Hierarchy (Ancestors)

COVID-19 Testing; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Serologic Tests; Immunologic Tests; Investigative Techniques; Immunologic Techniques

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 22, 2021
• First Posted: June 25, 2021
• Study Start: May 5, 2021
• Primary Completion (Estimated): May 1, 2028
• Study Completion (Estimated): June 1, 2028
• Last Updated: December 18, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

BE (1)