Use of BCG Vaccine as a Preventive Measure for COVID-19 in Health Care Workers


The disease promoted by coronavirus (COVID-19) is caused by Severe Acute Respiratory Syndrome (SARS) caused by Coronavirus type 2 (CoV2), being the first cases identified in December 2019 in China after exposure to the animal market in Wuhan city, China. From the first case to the present day, the COVID-19 epidemic has been identified in 185 countries, with the notification of 2,666,154 cases and 186,144 deaths. In Brazil, more than 45,757 cases and 2,906 confirmed deaths by COVID-19 have been confirmed (Visualized on Apr 23 2020). In our country, to date, testing for COVID-19 occurs only in severe cases and few centers offer the service to health care workers, a population at high risk of infection. BCG is a vaccine produced from a live attenuated strain derived from a Mycobacterium bovis isolate and is widely used worldwide as a tuberculosis (TB) vaccine, but there are studies demonstrating non-specific immunotherapeutic mechanisms of this vaccine that signal a possible relationship with the lowest morbidity and mortality associated with COVID-19 infections worldwide. The present study aims to analyze the role of BCG in the prevention of SARS-CoV-2 infection and also in the occurrence of severe forms of COVID-19 in addition to evaluating the immune response mediated by this vaccine in voluntary health care workers.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Prevention
    • Masking: Double (Participant, Care Provider)
  • Study Primary Completion Date: October 1, 2021


  • Biological: BCG vaccine
    • Using aseptic methods, 1 mL of Sterile Water for Injection, is added to one vial of vaccine. Gently swirl the vial until a homogenous suspension is obtained. Avoid forceful agitation which may cause clumping of the mycobacteria. Drop the immunizing dose of 0.1 mL of BCG VACCINE from the syringe and needle onto the cleansed surface of the skin.

Arms, Groups and Cohorts

  • Experimental: BCG vaccine
    • 0.1 ml of the reconstituted vaccine to be administered intradermally in the lower insertion of the deltoid muscle, preferably on the right side, in only one occasion
  • Placebo Comparator: 0.9% sodium chloride (NaCl) saline solution
    • 0.1 ml of 0.9% NaCl saline solution to be administered intradermally in the lower insertion of the deltoid muscle, preferably on the right side, in only one occasion

Clinical Trial Outcome Measures

Primary Measures

  • Compare the cumulative incidence of SARS-CoV-2 infection
    • Time Frame: 12 months
    • It is estimated that it will take 500 individuals in each of the comparison groups to ensure a statistical power of 85% for the detection of a risk difference of 5%, considering that the control group will have an accumulated incidence of SARS-CoV-2 infection of 10% after 6 months of follow-up, for a type I error of 5%.
  • Compare the cumulative incidence of severe forms of COVID-19
    • Time Frame: 12 months
    • With 500 individuals in each of the comparison groups the study will have a statistical power of approximately 75% for the detection of a risk difference of 2%, considering that the control group will have an accumulated incidence of more severe forms of COVID-19 of 2.5% after 6 months of follow-up, for a type I error of 5%.
  • Assess the BCG vaccine-mediated immune response in health care workers
    • Time Frame: 12 months
    • SARS-CoV2 infection is estimated to occur in approximately 10% of BCG-vaccinated healthcare professionals (experimental group) and in 30% of non-BCG-vaccinated healthcare professionals (placebo group) In this scenario, with the bearing of 500 health professionals in each arm, SARS-CoV2 infection is expected to be detected in 50 BCG-vaccinated professionals and 150 professionals not vaccinated with BCG. For each subgroup (vaccinated and not vaccinated with BCG) it will be possible to identify the predictive biomarkers of infection by comparing infected professionals with those who were not infected with SARS-CoV2.

Participating in This Clinical Trial

Inclusion Criteria

1. Individuals aged 18 ≥, male or female, not infected with SARS-CoV-2 2. Agreement to participate in the study by signing the Free Informed Consent (FIC) 3. Not being pregnant (in case of women able to become pregnant) Exclusion Criteria:

1. Professionals with a history of infection confirmed by SARS-CoV-2 or who have already presented a diagnosis of COVID-19 prior to the study 2. Individuals who have not underwent confirmatory tests for COVID-19 3. Breastfeeding 4. Individuals with primary or acquired immunodeficiency 5. Individuals affected by malignant neoplasms 6. Patients treated with high-dose corticosteroids (equivalent to the prednisone dose of 20 mg/day or more) for more than two weeks 7. Patients using other immunosuppressive therapies (antineoplastic chemotherapy, radiotherapy, among others) 8. Individuals with autoimmune diseases 9. Dermatological conditions at the vaccine site or generalized 10. Individuals under treatment for active tuberculosis 11. Individuals with a history of previous tuberculosis treatment 12. Individuals with febrile symptoms [body temperature ≥ 37.5 celsius degree (ºC) in the last 48h] 13. Participation in other prevention clinical trials for COVID-19 14. Report of vaccination with live microorganism administered in the month prior to randomization 15. Require that, if another vaccination with live microorganism is required, it is administered in the month following randomisation (If the other live vaccine can be administered on the same day, this exclusion criterion does not apply) 16. Known anaphylactic reaction to any ingredient in BCG vaccine 17. Adverse reaction prior to BCG vaccine [significant local reaction (abscess) or suppurative lymphadenitis] 18. BCG vaccine administered in the last year

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Universidade Federal do Rio de Janeiro
  • Collaborator
    • Ministry of Science and Technology, Brazil
  • Provider of Information About this Clinical Study
    • Principal Investigator: JOSE ROBERTO LAPA E SILVA, MD, MSc, PhD – Universidade Federal do Rio de Janeiro
  • Overall Contact(s)
    • Fernanda CQ Mello, PhD, +552139382887,


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