Table 1. Basic data from clinical trials evaluating the effect of BCG vaccination on COVID-19 and the TB status of subjects.
| Ref. | NCT No. | Countrya | Phase | Simple size | Clinical trial results | % of prior BCGb | BCG schedulerc | Participants were excluded fromd | ||
|---|---|---|---|---|---|---|---|---|---|---|
| ATB | LTBI | TB history | ||||||||
| 21 | NCT04328441 | Netherlands | Phase 3 | 1,309 | Did not reduce the incidence of SARS-CoV-2 infection in HCWs and the duration or severity of infection, but enhanced antibody production. | 17.3% | CBVSG | No | No | No |
| 22 | NCT04417335 | Netherlands | Phase 3 | 2,014 | BCG vaccination did not impact the occurrence of SARS-CoV-2 infection among older adult volunteers. However, it did enhance the cytokine responses and antibody titers. | 27.3% | CBVSG | No | No | No |
| 23 | NCT04379336 | South Africa | Phase 3 | 1,000 | BCG did not protect HCWs from SARS-CoV-2 infection or related severe COVID-19 disease and hospitalization. | 49.6% | CNBVPA | Unknown | No (48.5%)e | Unknown |
| 24 | NCT04327206 | Australia, Netherlands, Spain, the United Kingdom, and Brazil | Phase 3 | 3,988 | Vaccination with BCG-Denmark did not result in a lower risk of COVID-19 among health care workers than placebo. | 76.7% | CBVSG+PNBVA, CBVSG, NR, CNBVPA | No | No | No |
| 25 | NCT04648800 | Poland | Phase 3 | 342 | There was no meaningful association found between the frequency of suspected COVID-19 incidents and BCG-10 vaccination, tuberculin test results, or the number of scars. | Unknown | CNBVPA | No | No | Yes |
| 26 | NCT04659941 | Brazil | Phase 2b | 264 | BCG did not demonstrate a protective hazard ratio against COVID-19. | 93.2% | CNBVPA | No | No (21.3%)e | No |
| 27 | NCT02081326 | USA | Phase 2/3 | 144 | A cumulative incidence of 12.5% of placebo-treated and 1% of BCG-treated participants meets criteria for confirmed COVID-19, yielding an efficacy of 92%. | 0% | CBVSG | Yes | Unknown | Yes |
| 28 | NCT04328441 | Netherlands | Phase 3 | 1,511 | BCG vaccination offers some defense against potential COVID-19 infection in patients over 50 years old who have underlying health conditions. | 16.9% | CBVSG | Yes | Yes | Yes |
| 29 | NCT04414267 | Greece | Phase 3 | 301 | BCG vaccination can offer some protection against COVID-19 among individuals over 50 years old with underlying health conditions. | Unknown | CBVSG | Yes | Yes | Yes |
| 30 | CTRI/2020/07/026668 | India | Phase 3 | 495 | Did not significantly reduce the incidence of PCR-positive COVID-19 infection but did significantly reduce the incidence of clinically diagnosed COVID-19 infection in high-risk population. | Unknown | CNBVPA | No | No | No (4.8%) |
| 31 | NCT04369794 | Brazil | Phase 3 | 378 | BCG vaccine is safe and offers cross-protection against COVID-19 with potential humoral response modulation. | 94.0% | CNBVPA | No | No | No |
| 32 | RBR-4kjqtg | Brazil | Phase 2 | 138 | A second BCG Moscow vaccination was linked to a reduced rate of COVID-19 infections, although the findings were not statistically significant. | 86.3% | CNBVPA | No | No | No |
BCG = Bacillus Calmette-Guérin, COVID-19 = coronavirus disease 2019, TB = tuberculosis, NCT = clinical trials registration number, HCWs = health care workers, SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2, CNBVPA = current national BCG vaccination policy for all, CBVSG = current BCG vaccination for special groups, CBVSG+PNBVA = current BCG vaccination for special groups and past national BCG vaccination for all, ATB = active tuberculosis, LTBI = latent tuberculosis infection.
aThe country or region of the participants enrolled in the clinical trial.
bPrior BCG vaccinations.
cVaccine scheduler was obtained from http://www.bcgatlas.org/, accessed on August 11, 2023.
dAll participants were excluded from ATB, LTBI, and a history of TB prior to enrollment.
eLTBI status of each participant was determined by using TB QuantiFERON.