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

• Published in: Clinical microbiology and infection Vol. 28; no. 9; pp. 1278 - 1285
• Main Authors: ten Doesschate, Thijs, van der Vaart, Thomas W., Debisarun, Priya A., Taks, Esther, Moorlag, Simone J.C.F.M., Paternotte, Nienke, Boersma, Wim G., Kuiper, Vincent P., Roukens, Anna H.E., Rijnders, Bart J.A., Voss, Andreas, Veerman, Karin M., Kerckhoffs, Angele P.M., Oever, Jaap ten, van Crevel, Reinout, van Nieuwkoop, Cees, Lalmohamed, Arief, van de Wijgert, Janneke H.H.M., Netea, Mihai G., Bonten, Marc J.M., van Werkhoven, Cornelis H.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2022; The Author(s). Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases
• Subjects: BCG; COVID-19; Health care workers; Original; Randomized controlled trial; Trained immunity; COVID-19; Health care workers; Trained immunity; Randomized controlled trial; BCG
• ISSN: 1198-743X; 1469-0691
• DOI: 10.1016/j.cmi.2022.04.009

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. 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 ClinicalTrials.gov (NCT03987919). 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. During the COVID-19 pandemic, BCG-vaccination of HCW exposed to COVID-19 patients did not reduce unplanned absenteeism nor documented COVID-19.