Physicians at the National and Kapodistrian University of Athens ran a randomized trial of the BCG vaccine in patients over 65 leaving the hospital, betting on evidence that it trains the broader immune system to respond faster to unrelated infections, not just tuberculosis.
In an interim analysis of 150 of the 198 patients, new infections over a year occurred in 42.3 percent of those given placebo compared with 25.0 percent of those given BCG, a relative reduction of about 40 percent driven mostly by fewer respiratory infections of likely viral origin. Vaccinated participants also went roughly five weeks longer before their first infection.
The effect fits a growing body of evidence that some vaccines retrain innate immune cells in ways that reach beyond their original target, a phenomenon researchers call trained immunity. The trial was run at a single center in Greece, and larger trials followed; the biggest, BRACE, found BCG did not protect health workers against COVID-19.
Read the original study
Giamarellos-Bourboulis et al., Cell, 2020 · doi.org/10.1016/j.cell.2020.08.051
A century-old shot, a new job.
Source
- Giamarellos-Bourboulis, E. J., Tsilika, M., Moorlag, S., Antonakos, N., Kotsaki, A., Domínguez-Andrés, J., Kyriazopoulou, E., Gkavogianni, T., Adami, M.-E., Damoraki, G., Koufargyris, P., Karageorgos, A., Bolanou, A., Koenen, H., van Crevel, R., Droggiti, D.-I., Renieris, G., Papadopoulos, A., & Netea, M. G. (2020). Activate: Randomized Clinical Trial of BCG Vaccination against Infection in the Elderly. Cell, 183(2), 315–323.e9. https://doi.org/10.1016/j.cell.2020.08.051