BCG vaccination history associates with decreased SARS-CoV-2 seroprevalence across a diverse cohort of health care workers
Magali Noval Rivas, Joseph E. Ebinger, Min Wu, Nancy Sun, Jonathan Braun, Kimia Sobhani, Jennifer E. Van Eyk, Susan Cheng, Moshe Arditi
Magali Noval Rivas, Joseph E. Ebinger, Min Wu, Nancy Sun, Jonathan Braun, Kimia Sobhani, Jennifer E. Van Eyk, Susan Cheng, Moshe Arditi
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Clinical Research and Public Health

BCG vaccination history associates with decreased SARS-CoV-2 seroprevalence across a diverse cohort of health care workers

Abstract

BACKGROUND Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused more than 1 million deaths worldwide; thus, there is an urgent need to develop preventive and therapeutic strategies. The antituberculosis vaccine bacillus Calmette-Guérin (BCG) demonstrates nonspecific, protective innate immune–boosting effects. Here, we determined whether a history of BCG vaccination was associated with decreased SARS-CoV-2 infection and seroconversion in a longitudinal, retrospective observational study of a diverse cohort of health care workers (HCWs).METHODS We assessed SARS-CoV-2 seroprevalence and collected medical questionnaires, which included information on BCG vaccination status and preexisting demographic and clinical characteristics, from an observational cohort of HCWs in a multisite Los Angeles health care organization. We used multivariate analysis to determine whether a history of BCG vaccination was associated with decreased rates of SARS-CoV-2 infection and seroconversion.RESULTS Of the 6201 HCWs, 29.6% reported a history of BCG vaccination, whereas 68.9% had not received BCG vaccination. Seroprevalence of anti–SARS-CoV-2 IgG as well as the incidence of self-reported clinical symptoms associated with coronavirus disease 2019 (COVID-19) were markedly decreased among HCWs with a history of BCG vaccination compared with those without BCG vaccination. After adjusting for age and sex, we found that a history of BCG vaccination, but not meningococcal, pneumococcal, or influenza vaccination, was associated with decreased SARS-CoV-2 IgG seroconversion.CONCLUSIONS A history of BCG vaccination was associated with a decrease in the seroprevalence of anti–SARS-CoV-2 IgG and a lower number of participants who self-reported experiencing COVID-19–related clinical symptoms in this cohort of HCWs. Therefore, large randomized, prospective clinical trials of BCG vaccination are urgently needed to confirm whether BCG vaccination can confer a protective effect against SARS-CoV-2 infection.

Authors

Magali Noval Rivas, Joseph E. Ebinger, Min Wu, Nancy Sun, Jonathan Braun, Kimia Sobhani, Jennifer E. Van Eyk, Susan Cheng, Moshe Arditi

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Figure 1

Flow chart of this retrospective observational study.

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Flow chart of this retrospective observational study. A total of 6679 HC...
A total of 6679 HCWs were recruited in this study. Self-reported information about a previous COVID-19 diagnosis, a positive or negative SARS-CoV-2 RT-PCR test, experience of COVID-19–related symptoms, as well as BCG, meningococcal, Pneumovax, and influenza vaccination status were collected retrospectively with an electronic survey. Among the 6679 participants, 478 did not provide a blood sample to measure the anti–SARS-CoV-2 IgG index and were thus excluded from the analysis. Of the remaining 6201 participants, 1836 reported a previous history of BCG vaccination, 1842 reported a previous meningococcal vaccination, 1007 reported receiving a Pneumovax vaccination, and 6014 reported receiving an influenza vaccination.