Izaak Van Evercooren

Adapted XBB.1.5 vaccine effectiveness against severe COVID-19 outcomes among immunocompromised persons in 2023-24 in six European countries: a VEBIS-EHR network study.

Journal: Expert review of vaccines

Published: July 27, 2026

Unmeasured confounding and misclassification in studies estimating vaccine effectiveness against hospitalisation and death using electronic health records (EHRs): an evaluation of a multi-country European retrospective cohort study.

Journal: BMC medical research methodology

Published: August 06, 2025

Effectiveness of JN.1 monovalent COVID-19 vaccination in EU/EEA countries between October 2024 and January 2025: a VEBIS electronic health record network study.

Journal: Vaccine

Published: July 16, 2025

Effectiveness of the 2023 Autumn XBB.1.5 COVID-19 Booster During Summer 2024 in the EU/EEA: A VEBIS Electronic Health Record Network Study.

Journal: Influenza and other respiratory viruses

Published: May 12, 2025

Comparison of two methods for the estimation of COVID-19 vaccine effectiveness of the autumnal booster within the VEBIS-EHR network in 2022/23.

Journal: Epidemiology and infection

Published: March 16, 2025

Averted mortality by COVID-19 vaccination in Belgium between 2021 and 2023.

Journal: Vaccine

Published: March 12, 2025

Monovalent XBB.1.5 COVID-19 vaccine effectiveness against hospitalisations and deaths during the Omicron BA.2.86/JN.1 period among older adults in seven European countries: A VEBIS-EHR network study.

Journal: Expert review of vaccines

Published: November 13, 2024

Effectiveness of XBB.1.5 Monovalent COVID-19 Vaccines During a Period of XBB.1.5 Dominance in EU/EEA Countries, October to November 2023: A VEBIS-EHR Network Study.

Journal: Influenza and other respiratory viruses

Published: March 15, 2024

Relative vaccine effectiveness against COVID-19 hospitalisation in persons aged ≥ 65 years: results from a VEBIS network, Europe, October 2021 to July 2023.

Journal: Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin

Published: January 05, 2024

Area and individual level analyses of demographic and socio-economic disparities in COVID-19 vaccination uptake in Belgium.

Journal: Vaccine: X

Published: December 07, 2023

Factors underlying COVID-19 booster vaccine uptake among adults in Belgium.

Journal: BMC research notes

Published: June 23, 2023

Monitoring COVID-19 vaccine effectiveness against COVID-19 hospitalisation and death using electronic health registries in ≥65 years old population in six European countries, October 2021 to November 2022.

Journal: Influenza and other respiratory viruses

Published: May 27, 2023

Adapted XBB.1.5 vaccine effectiveness against severe COVID-19 outcomes among immunocompromised persons in 2023-24 in six European countries: a VEBIS-EHR network study.

Adapted XBB.1.5 vaccine effectiveness against severe COVID-19 outcomes among immunocompromised persons in 2023-24 in six European countries: a VEBIS-EHR network study.

Unmeasured confounding and misclassification in studies estimating vaccine effectiveness against hospitalisation and death using electronic health records (EHRs): an evaluation of a multi-country European retrospective cohort study.

Unmeasured confounding and misclassification in studies estimating vaccine effectiveness against hospitalisation and death using electronic health records (EHRs): an evaluation of a multi-country European retrospective cohort study.

Effectiveness of JN.1 monovalent COVID-19 vaccination in EU/EEA countries between October 2024 and January 2025: a VEBIS electronic health record network study.

Effectiveness of JN.1 monovalent COVID-19 vaccination in EU/EEA countries between October 2024 and January 2025: a VEBIS electronic health record network study.

Effectiveness of the 2023 Autumn XBB.1.5 COVID-19 Booster During Summer 2024 in the EU/EEA: A VEBIS Electronic Health Record Network Study.

Effectiveness of the 2023 Autumn XBB.1.5 COVID-19 Booster During Summer 2024 in the EU/EEA: A VEBIS Electronic Health Record Network Study.

Comparison of two methods for the estimation of COVID-19 vaccine effectiveness of the autumnal booster within the VEBIS-EHR network in 2022/23.

Comparison of two methods for the estimation of COVID-19 vaccine effectiveness of the autumnal booster within the VEBIS-EHR network in 2022/23.

Averted mortality by COVID-19 vaccination in Belgium between 2021 and 2023.

Averted mortality by COVID-19 vaccination in Belgium between 2021 and 2023.

Monovalent XBB.1.5 COVID-19 vaccine effectiveness against hospitalisations and deaths during the Omicron BA.2.86/JN.1 period among older adults in seven European countries: A VEBIS-EHR network study.

Monovalent XBB.1.5 COVID-19 vaccine effectiveness against hospitalisations and deaths during the Omicron BA.2.86/JN.1 period among older adults in seven European countries: A VEBIS-EHR network study.

Effectiveness of XBB.1.5 Monovalent COVID-19 Vaccines During a Period of XBB.1.5 Dominance in EU/EEA Countries, October to November 2023: A VEBIS-EHR Network Study.

Effectiveness of XBB.1.5 Monovalent COVID-19 Vaccines During a Period of XBB.1.5 Dominance in EU/EEA Countries, October to November 2023: A VEBIS-EHR Network Study.

Relative vaccine effectiveness against COVID-19 hospitalisation in persons aged ≥ 65 years: results from a VEBIS network, Europe, October 2021 to July 2023.

Relative vaccine effectiveness against COVID-19 hospitalisation in persons aged ≥ 65 years: results from a VEBIS network, Europe, October 2021 to July 2023.

Area and individual level analyses of demographic and socio-economic disparities in COVID-19 vaccination uptake in Belgium.

Area and individual level analyses of demographic and socio-economic disparities in COVID-19 vaccination uptake in Belgium.

Factors underlying COVID-19 booster vaccine uptake among adults in Belgium.

Factors underlying COVID-19 booster vaccine uptake among adults in Belgium.

Monitoring COVID-19 vaccine effectiveness against COVID-19 hospitalisation and death using electronic health registries in ≥65 years old population in six European countries, October 2021 to November 2022.

Monitoring COVID-19 vaccine effectiveness against COVID-19 hospitalisation and death using electronic health registries in ≥65 years old population in six European countries, October 2021 to November 2022.

Relative vaccine effectiveness against COVID-19 hospitalisation in persons aged ≥ 65 years: results from a VEBIS network, Europe, October 2021 to July 2023.

Relative vaccine effectiveness against COVID-19 hospitalisation in persons aged ≥ 65 years: results from a VEBIS network, Europe, October 2021 to July 2023.