This article is part of Harvard Medical School’s continuing coverage of COVID-19.
Researchers at Harvard Medical School and Massachusetts General Hospital have published a new paper in Cell Reports Medicine demonstrating the protective potential of multiple doses of the bacillus Calmette-Guerin (BCG) tuberculosis vaccine against COVID-19 and other infectious diseases.
In a double-blind, placebo-controlled study of patients with type 1 diabetes conducted at the start of the pandemic, before COVID-specific vaccines were available, the researchers found that 12.5 percent of placebo-treated individuals and 1 percent of BCG-treated individuals met criteria for confirmed COVID-19, yielding a vaccine effectiveness of 92 percent.
The BCG-vaccinated group also displayed protective effects against other infectious diseases, including fewer symptoms, lesser severity and fewer infectious disease events per patient. No BCG-related systemic adverse events occurred.