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. 2024 Nov 19;12(11):1295.
doi: 10.3390/vaccines12111295.

Incidence of SARS-CoV-2 Infection Among European Healthcare Workers and Effectiveness of the First Booster COVID-19 Vaccine, VEBIS HCW Observational Cohort Study, May 2021-May 2023

Camelia Savulescu  1 , Albert Prats-Uribe  1 , Kim Brolin  2 , Zvjezdana Lovrić Makarić  3 , Anneli Uusküla  4 , Georgios Panagiotakopoulos  5 , Colm Bergin  6   7 , Catherine Fleming  8   9 , Antonella Agodi  10   11 , Paolo Bonfanti  12 , Rita Murri  13   14 , Viesturs Zvirbulis  15 , Dace Zavadska  16 , Konstanty Szuldrzynski  17 , Ausenda Machado  18 , Corneliu Petru Popescu  19   20 , Mihai Craiu  20   21 , Maria Cisneros  22   23 , Miriam Latorre-Millán  24 , Goranka Petrović  3 , Liis Lohur  25 , Kyriaki Tryfinopoulou  5 , Jonathan McGrath  6 , Lauren Ferguson  8 , Martina Barchitta  10 , Anna Spolti  12 , Katleen de Gaetano Donati  13   14 , Ilze Abolina  15 , Dagne Gravele  16 , Vânia Gaio  18 , Simin Aysel Florescu  19   20 , Mihaela Lazar  26 , Pilar Subirats  27 , Laura Clusa Cuesta  24 , Gordan Sarajlić  3 , Marina Amerali  5 , Jacklyn Sui  6 , Claire Kenny  8 , Venerando Rapisarda  11   28 , Marianna Rossi  12 , Silvia Lamonica  13   14 , Dainis Krievins  15 , Elza Anna Barzdina  16 , Ana Palmira Amaral  29 , Alma Gabriela Kosa  19 , Victor Daniel Miron  20   21 , Carmen Muñoz-Almagro  22   23   30 , Ana María Milagro  24 , Sabrina Bacci  2 , Piotr Kramarz  2 , Anthony Nardone  1 , The Vebis Hcw Ve Study Group
Affiliations

Incidence of SARS-CoV-2 Infection Among European Healthcare Workers and Effectiveness of the First Booster COVID-19 Vaccine, VEBIS HCW Observational Cohort Study, May 2021-May 2023

Camelia Savulescu et al. Vaccines (Basel). .

Abstract

Background: European countries have included healthcare workers (HCWs) among priority groups for COVID-19 vaccination. We established a multi-country hospital network to measure the SARS-CoV-2 incidence and effectiveness of COVID-19 vaccines among HCWs against laboratory-confirmed SARS-CoV-2 infection. Methods: HCWs from 19 hospitals in 10 countries participated in a dynamic prospective cohort study, providing samples for SARS-CoV-2 testing at enrolment and during weekly/fortnightly follow-up. We measured the incidence during pre-Delta (2 May-6 September 2021), Delta (7 September-14 December 2021), and Omicron (15 December 2021-2 May 2023) waves. Using Cox regression, we measured the relative vaccine effectiveness (rVE) of the first COVID-19 booster dose versus primary course alone during Delta and Omicron waves. Results: We included a total of 3015 HCWs. Participants were mostly female (2306; 79%), with a clinical role (2047; 68%), and had a median age of 44 years. The overall incidence of SARS-CoV-2 infection was 3.01/10,000 person-days during pre-Delta, 4.21/10,000 during Delta, and 23.20/10,000 during Omicron waves. rVE was 59% (95% CI: -25; 86) during Delta and 22% (1; 39) during Omicron waves. rVE was 51% (30; 65) 7-90 days after the first booster dose during the Omicron wave. Conclusions: The incidence of SARS-CoV-2 infection among HCWs was higher during the Omicron circulation period. The first COVID-19 vaccine booster provided additional protection against SARS-CoV-2 infection compared to primary course vaccination when recently vaccinated <90 days. This multi-country HCW cohort study addressing infection as the main outcome is crucial for informing public health interventions for HCWs.

Keywords: COVID-19; Europe; SARS-CoV-2; healthcare workers; vaccine effectiveness.

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Conflict of interest statement

A.P.-U. reports payment under the EMA DARWIN EU project outside of the submitted work. P.B. reports receiving consulting fees from VIIV, MSD, and GILEAD, and speaker fees from VIIV, GILEAD, ASTRAZENECA, and PFIZER outside of the submitted work. M.L.-M., A.M.M. and L.C.C report additional support received from the ISIDORe (EATRIS) Network for carrying out the local SARS-CoV-2 sequencing. C.P.P. and S.A.F. report speaker fees from and participation in the advisory board of Pfizer and MSD. S.A.F. also reports participation in the advisory board of Gilead. J.S. reports support from Takeda Pharmaceutical for attending the ESID 2022 conference. C.M.-A. reports speaker fees from MSD, Pfizer, and Sanofi. All other authors declare no conflicts of interest related to this work.

Figures

Figure 1
Figure 1
Data inclusion and exclusion flow chart, VEBIS HCW study, 2 May 2023.
Figure 2
Figure 2
COVID-19 vaccine brands by dose and time, multi-country VEBIS HCW COVID-19 VE study, May 2021–May 2023.
Figure 3
Figure 3
Incidence rate of laboratory-confirmed SARS-CoV-2 infection and number of samples sequenced in 11/19 sites, VEBIS HCW study, May 2021–May 2023.
See this image and copyright information in PMC

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