ASCO 2021: Effect of BCG Exposure on Severity of COVID-19 Infection: A COVID-19 and Cancer Consortium (CCC19) Study

(  Oncology patients experience more severe disease outcomes from COVID-19 infection than the general population. BCG is a live bovine tuberculosis bacillus with immunotherapeutic effects in urothelial cancers, and it is also used as a vaccination against Mycobacterium tuberculosis in parts of the world. As BCG vaccination has been associated with broad protection against viral pathogens, BCG exposure through vaccination or intravesical therapy may modulate host immunity and reduce the severity of COVID-19 infection. At the 2021 ASCO virtual annual meeting, Dr. Andrew Schmidt and colleagues presented results of their study assessing the effect of BCG exposure on COVID-19 severity in oncology patients from the COVID-19 Cancer Consortium (CCC19) registry.

The CCC19 registry (NCT04354701) was used to identify patients with prior BCG exposure. Cohort A received intravesical treatment for bladder carcinoma, and cohort B received prior BCG vaccination. Each cohort was matched 3:1 to non-BCG-exposed controls by age, sex, race, primary cancer type, cancer status, ECOG performance status and calendar time of COVID-19 infection. The primary endpoint was COVID-19 severity reported on an ordinal scale (uncomplicated, hospitalized, admitted to ICU +/- ventilated, died within 30 days) of patients exposed to prior BCG compared to matched non-exposed controls.

As of February 6, 2021, there were 124 patients included with BCG exposure, of which 68 patients had bladder carcinoma who had received intravesical BCG (Cohort A), and 64 cancer patients with prior BCG vaccination (Cohort B). The median age was 76 years (IQR 69-83) for Cohort A and 67 years (IQR 62-74) for Cohort B. Bladder cancer patients were predominately male (78%) versus 55% for Cohort B. Patients with a performance status >= 2 were uncommon, with only 18% in Cohort A and 16% in Cohort B. The table of baseline characteristics is as follows:


Ultimately, COVID-19 illness severity was no different in patients exposed to prior intravesicular BCG (p = 0.87) and no different in patients exposed to prior intradermal BCG vaccination (p = 0.60):


Dr. Schmidt concluded his presentation with the following take-home points:

  • In this moderately sized retrospective cohort, no protective effect was apparent for prior BCG exposure in reducing the peak severity of COVID-19 infection
  • Oncology patients remain at risk of poor outcomes following COVID-19 infection, and it is important to continue the search for factors and interventions that may be protective or harmful in the oncology population through large consortiums such as CCC19
  • BCG vaccination as an intervention is being investigated in eight prospective clinical trials


Presented by: Andrew L. Schmidt, MD, Lank Center for Genitourinary Oncology, Dana-Farber Cancer Institute, Boston, MA

Co-Authors: Ziad Bakouny, Chris Labaki, Babar Bashir, Jessica M. Clement, Natasha Catherine Edwin, Daniel Blake Flora, Jennifer Girard, Shuchi Gulati, Clara Hwang, Chinmay Jani, Gilberto Lopes, Ruben A. Mesa, Gil Redelman-Sidi, Sanjay Mishra, Jeremy Lyle Warner, Toni K. Choueiri; Dana Farber Cancer Institute - (Individuals), Boston, MA; Sidney Kimmel Cancer Center, Thomas Jefferson University Hospital, Philadelphia, PA; University of Connecticut Health Center Carole and Ray Neag Comprehensive Cancer Center, Farmington, CT; Cleveland Clinic, Cleveland, OH; Univ Hosp/Univ of Cincinnati, Cincinnati, OH; University of Michigan Rogel Cancer Center, Michigan, MI; University of Cincinnati Medical Center, Cincinnati, OH; Henry Ford Health System, Detroit, MI; Mount Auburn Hospital-Harvard Medical School, Cambridge, MA; University of Miami Miller School of Medicine, Miami, FL; UT Health San Antonio, San Antonio, TX; Memorial Sloan Kettering Cancer Center, New York, NY; Vanderbilt University Medical Center, Nashville; Vanderbilt-Ingram Cancer Center, Nashville, TN; Dana-Farber Cancer Institute, The Lank Center for Genitourinary Oncology, Boston, MA

Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia Twitter: @zklaassen_md at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting, Virtual Annual Meeting #ASCO21, June, 4-8, 2021
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