Bacillus Calmette-Guérin vaccine to reduce healthcare worker absenteeism in COVID-19 pandemic, a randomized controlled trial

Thijs Ten Doesschate*, Thomas W van der Vaart, Priya A Debisarun, Esther Taks, Simone J C F M Moorlag, Nienke Paternotte, Wim G Boersma, Vincent P Kuiper, Anna H E Roukens, Bart J A Rijnders, Andreas Voss, Karin M Veerman, Angele P M Kerckhoffs, Jaap Ten Oever, Reinout van Crevel, Cees van Nieuwkoop, Arief Lalmohamed, Janneke H H M van de Wijgert, Mihai G Netea, Marc J M BontenCornelis H van Werkhoven*

*Corresponding author for this work

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OBJECTIVES: The COVID-19 pandemic increases healthcare worker (HCW) absenteeism. The bacillus Calmette-Guérin (BCG) vaccine may provide non-specific protection against respiratory infections through enhancement of trained immunity. We investigated the impact of BCG vaccination on HCW absenteeism during the COVID-19 pandemic.

METHODS: HCWs exposed to COVID-19 patients in nine Dutch hospitals were randomized to BCG vaccine or placebo in a 1:1 ratio, and followed for one year using a mobile phone application. The primary endpoint was the self-reported number of days of unplanned absenteeism for any reason. Secondary endpoints included documented COVID-19, acute respiratory symptoms or fever. This was an investigator-funded study, registered at (NCT03987919).

RESULTS: In March/April 2020, 1511 HCWs were enrolled. The median duration of follow-up was 357 person-days (interquartile range [IQR], 351 to 361). Unplanned absenteeism for any reason was observed in 2.8% of planned working days in the BCG group and 2.7% in the placebo group (adjusted relative risk 0.94; 95% credible interval, 0.78-1.15). Cumulative incidences of documented COVID-19 were 14.2% in the BCG and 15.2% in the placebo group (adjusted hazard ratio (aHR) 0.94; 95% confidence interval (CI), 0.72-1.24). First episodes of self-reported acute respiratory symptoms or fever occurred in 490 (66.2%) and 443 (60.2%) participants, respectively (aHR: 1.13; 95% CI, 0.99-1.28). Thirty-one serious adverse events were reported (13 after BCG, 18 after placebo), none considered related to study medication.

CONCLUSIONS: During the COVID-19 pandemic, BCG-vaccination of HCW exposed to COVID-19 patients did not reduce unplanned absenteeism nor documented COVID-19.

Original languageEnglish
Pages (from-to)1278-1285
Number of pages8
JournalClinical Microbiology and Infection
Issue number9
Publication statusE-pub ahead of print - 27 Apr 2022

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Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.


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