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December 5, 2024 – A groundbreaking study has revealed that administering the Bacillus Calmette-Guérin (BCG) vaccine during the active phase of COVID-19 may significantly reduce the risk of developing long COVID symptoms. The findings, published in the Journal of Internal Medicine, offer a new avenue for mitigating the prolonged effects of the virus.
Study Overview
The phase 3 clinical trial, led by researchers Mehrsa Jalalizadeh and Keini Buosi at the State University of Campinas, Brazil, began in early 2020. It aimed to explore the effects of the BCG vaccine on adults with mild to moderate COVID-19. Patients who tested positive for SARS-CoV-2 were randomly assigned to receive either 0.1 mL of intradermal BCG (191 participants) or a saline placebo (202 participants) within 14 days of symptom onset.
Participants were followed up at regular intervals—7, 14, 21, and 45 days, and 6 and 12 months post-injection—to assess the vaccine’s impact on long COVID symptoms. The trial primarily focused on cognitive and physical health outcomes, with 157 BCG and 142 placebo recipients completing the 6-month follow-up, and 97 BCG and 95 placebo recipients completing the 12-month follow-up.
Key Findings
The study demonstrated promising results:
- Reduced Long COVID Symptoms: At 12 months, BCG recipients reported fewer issues with sleep (P = .027), concentration (P = .009), memory (P = .009), and vision (P = .022) compared to the placebo group. The overall long-COVID score was also significantly lower (P = .002).
- Hearing Improvements: At 6 months, hearing problems were less frequent among BCG recipients (odds ratio [OR], 0.26; 95% CI, 0.045-1.0; P = .044).
- Sex-Specific Effects: BCG reduced hair loss in men (P = .031) but caused a slight, statistically nonsignificant increase in women. Male participants were also found to be at higher risk for long COVID and cognitive dysfunction at both follow-up points.
Clinical Implications
The study’s authors suggest that BCG immunotherapy, administered during active illness, may offer benefits beyond its traditional use in tuberculosis prevention. “These findings suggest that BCG immunotherapy for an existing ailment may be superior to prophylaxis in healthy individuals,” the researchers noted.
Limitations and Future Research
While the results are encouraging, the study had limitations. Researchers did not test participants for prior mycobacterial exposure, and a significant loss to follow-up at 12 months may have introduced bias. Further studies are needed to confirm these findings and explore the mechanisms underlying BCG’s effects on long COVID.
Support and Disclosures
The study was supported by multiple Brazilian government agencies, including the National Immunization Program and the National Council for Scientific and Technological Development. The authors declared no conflicts of interest.
As the world continues to grapple with the long-term impacts of COVID-19, this research adds a valuable tool to the arsenal against the virus’s lingering effects.
