International Journal of Infectious Diseases (May 2023)

The effect of BCG vaccination on infection and antibody levels against SARS-CoV-2—The results of ProBCG: a multicenter randomized clinical trial in Brazil

  • Ana Paula Santos,
  • Guilherme Loureiro Werneck,
  • Ana Paula Razal Dalvi,
  • Carla Conceição dos Santos,
  • Paulo Fernando Guimarães Morando Marzocchi Tierno,
  • Hanna Silva Condelo,
  • Bruna Macedo,
  • Janaina Aparecida de Medeiros Leung,
  • Jeane de Souza Nogueira,
  • Ludmila Malvão,
  • Rafael Galliez,
  • Roberta Aguiar,
  • Roberto Stefan,
  • Sabrina Modena Knackfuss,
  • Elisangela Costa da Silva,
  • Terezinha Marta Pereira Pinto Castineiras,
  • Roberto de Andrade Medronho,
  • José Roberto Lapa e Silva,
  • Rogério Lopes Rufino Alves,
  • Luís Cristóvão de Moraes Sobrino Porto,
  • Luciana Silva Rodrigues,
  • Afrânio Lineu Kritski,
  • Fernanda Carvalho de Queiroz Mello

Journal volume & issue
Vol. 130
pp. 8 – 16

Abstract

Read online

ABSTRACT: Objectives: Evatuate if Bacillus Calmette-Guérin (BCG) vaccine could be used as a tool against SARS-CoV-2 based on the concept of trained immunity. Methods: A multicenter, double-blinded, randomized clinical trial recruited health care workers (HCWs) in Brazil. The incidence rates of COVID-19, clinical manifestations, absenteeism, and adverse events among HCWs receiving BCG vaccine (Moreau or Moscow strains) or placebo were compared. BCG vaccine-mediated immune response before and after implementing specific vaccines for COVID-19 (CoronaVac or COVISHIELD) was analyzed. Cox proportional hazard and linear mixed effect modeling were used. Results: A total of 264 volunteers were included for analysis (BCG = 134 and placebo = 130). The placebo group presented a COVID-19 cumulative incidence of 0.75% vs 0.52% of BCG. The Moreau strain also presented a higher incidence rate (1.60% × 0.22%). BCG did not show a protective hazard ratio against COVID-19. In addition, the log (immunoglobulin G) level against SARS-CoV-2 presented a higher increase in the BCG group, whether or not participants had COVID-19, but also without statistical significance. Conclusion: Our results suggest that BCG has a tendency of protection against SARS-CoV-2 and higher immunoglobulin G levels than placebo. The clinical trial was registered at https://clinicaltrials.gov/ (NCT04659941).

Keywords