4. Miller A, Reandelar MJ, Fasciglione K, Roumenova V, Li Y, Otazu GH. Correlation between universal BCG vaccination policy and reduced mortality for COVID-19. Preprint medRxiv at
https://doi.org/10.1101/2020.03.24.20042937 (2020).
6. Luca S, Mihaescu T. History of BCG vaccine. Maedica (Bucur) 2013;8:53-8.
12. Mangtani P, Nguipdop-Djomo P, Keogh RH, Trinder L, Smith PG, Fine PE, et al. Observational study to estimate the changes in the effectiveness of bacillus Calmette-Guerin (BCG) vaccination with time since vaccination for preventing tuberculosis in the UK. Health Technol Assess 2017;21:1-54.
13. Colditz GA, Brewer TF, Berkey CS, Wilson ME, Burdick E, Fineberg HV, et al. Efficacy of BCG vaccine in the prevention of tuberculosis: meta-analysis of the published literature. JAMA 1994;271:698-702.
14. Fine PE. Variation in protection by BCG: implications of and for heterologous immunity. Lancet 1995;346:1339-45.
15. Venkataswamy MM, Goldberg MF, Baena A, Chan J, Jacobs WR Jr, Porcelli SA. In vitro culture medium influences the vaccine efficacy of
Mycobacterium bovis BCG. Vaccine 2012;30:1038-49.
16. Abubakar I, Pimpin L, Ariti C, Beynon R, Mangtani P, Sterne JA, et al. Systematic review and meta-analysis of the current evidence on the duration of protection by bacillus CalmetteGuerin vaccination against tuberculosis. Health Technol Assess 2013;17:1-372.
18. Sterne JA, Rodrigues LC, Guedes IN. Does the efficacy of BCG decline with time since vaccination? Int J Tuberc Lung Dis 1998;2:200-7.
20. Aronson NE, Santosham M, Comstock GW, Howard RS, Moulton LH, Rhoades ER, et al. Long-term efficacy of BCG vaccine in American Indians and Alaska Natives: a 60-year follow-up study. JAMA 2004;291:2086-91.
23. Arts RJ, Moorlag SJ, Novakovic B, Li Y, Wang SY, Oosting M, et al. BCG vaccination protects against experimental viral infection in humans through the induction of cytokines associated with trained immunity. Cell Host Microbe 2018;23:89-100.
24. Leentjens J, Kox M, Stokman R, Gerretsen J, Diavatopoulos DA, van Crevel R, et al. BCG vaccination enhances the immunogenicity of subsequent influenza vaccination in healthy volunteers: a randomized, placebo-controlled pilot study. J Infect Dis 2015;212:1930-8.
27. Zhao X, Zhang B, Li P, Ma C, Gu J, Hou P, et al. Incidence, clinical characteristics and prognostic factor of patients with COVID-19: a systematic review and meta-analysis. Preprint medRxiv at
https://doi.org/10.1101/2020.03.17.20037572 (2020).
29. Prompetchara E, Ketloy C, Palaga T. Immune responses in COVID-19 and potential vaccines: Lessons learned from SARS and MERS epidemic. Asian Pac J Allergy Immunol 2020;38:1-9.
35. Lahariya C. A brief history of vaccines and vaccination in India. Indian J Med Res 2014;139:491-511.
39. Gruber C, Meinlschmidt G, Bergmann R, Wahn U, Stark K. Is early BCG vaccination associated with less atopic disease? An epidemiological study in German preschool children with different ethnic backgrounds. Pediatr Allergy Immunol 2002;13:177-81.
41. Ricco M, Gualerzi G, Ranzieri S, Bragazzi NL. Stop playing with data: there is no sound evidence that Bacille CalmetteGuerin may avoid SARS-CoV-2 infection (for now). Acta Biomed 2020;91:207-13.
42. ClinicalTrials.gov [Internet]. Bethesda, MD: U.S National Library of Medicine; 2020 [cited 2020 May 5]. Available from:
https://clinicaltrials.gov/.