Countries that had compulsory bacillus Calmette-Guérin (BCG) vaccination at least until 2000 appear to have built up a degree of “herd immunity” against COVID-19, a new study suggests.
BCG vaccination is usually given at birth or during childhood to protect against tuberculosis (TB). But there is also evidence that it protects against other respiratory infections and lung cancer. In addition, it is an effective treatment for some forms of bladder cancer.
A study in 2018 found that the vaccine appeared to “reprogram” immune cells to produce more of a particular immune signalling molecule. This, in turn, boosted immunity against viral infection. The studies found that having mandatory BCG vaccination significantly “flattened the curve” of the initial spread of COVID-19 throughout the populations studied.
Source: Medscape