BCG vaccine protects against long COVID development, finds study

A new study published in the Journal of Internal Medicine showed that it may be possible to prevent the formation of protracted COVID-19 by administering the Bacillus Calmette-Guérin (BCG) vaccination during the active phase of the virus.

The common cold is mostly caused by coronaviruses (CoVs), which are usually considered to be nonlethal human infections. Because of its similarities to the previous human coronavirus disease, SARS, which began in the Guangdong region of China in 2002 and spread to 27 countries before ending in mid-2003. Also, its symptoms are similar to those of severe acute respiratory distress (SARD). Demographic studies show that the epidemiological characteristics of COVID-19 differ from those of SARS. Early on in an infection, SARS-CoV-2 can cause little to no symptoms since it can replicate in both the upper and lower respiratory tracts.

The Bacillus Calmette-Guérin (BCG) vaccination is commonly used to prevent tuberculosis (TB) in infants. The BCG vaccination may have a protective benefit against newborn mortality through innate immunological epigenetic mechanisms or nonspecific heterologous protection against other illnesses, according to epidemiological and randomized research.

BCG injections throughout the COVID-19 convalescence period were safe and improved acute phase recovery from anosmia and dysgeusia. In order to describe the long-term outcomes of the BATTLE trial and the BCG vaccination in people with moderate COVID-19, this study was carried out.

The patients in this study received a placebo and the BCG intradermal vaccination. The 6-month follow-up involved 157 BCG and 142 placebo participants, whereas the 12-month follow-up involved 97 BCG and 95 placebo recipients. Mechanistic studies and long-term COVID symptoms were conducted.

At 6 months, BCG helped with hearing issues; at 12 months, it helped with sleep, focus, memory, and vision issues. The reduction of long-term COVID-19 symptoms at the 6- and 12-month follow-ups was validated by sensitivity analysis. At 6 months, the crossover interaction of BCG paradoxically caused a reduction in male hair loss and an increase in female hair loss.

Inhibition of blood Fas ligand expression and enhanced activation of IL10, IL6, interferon-induced transmembrane protein 3, and angiotensin-converting enzyme 2 in cultured human macrophages are likely the mechanisms by which BCG immunomodulation occurs. Overall, long-term follow-up with BATTLE study subjects demonstrated that BCG vaccine, if given during the COVID-19 convalescence stage, protects against long-term COVID development.

Source:

Jalalizadeh, M., Buosi, K., Giacomelli, C. F., Leme, P. A. F., Ferrari, K. L., Dionato, F. A. V., Brito, W. R. S., Brunetti, N. S., Maia, A. R., Morari, J., Pagliarone, A. C., Farias, A. S., Velloso, L. A., Queiroz, M. A. F., Vallinoto, A. C. R., Bajgelman, M. C., & Reis, L. O. (2024). Therapeutic BCG vaccine protects against long COVID: The BATTLE randomized clinical trial. In Journal of Internal Medicine (Vol. 297, Issue 1, pp. 60–78). Wiley. https://doi.org/10.1111/joim.20033