Background: The 2019 severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic continued into 2020, and the coronavirus disease-2019 (COVID-19) associated death toll increased.

Objectives: To analyze COVID-19 death rates in European countries or regions to determine whether there was a significant association between bacillus Calmette-Guérin (BCG) vaccination policy and lower rates of COVID-19 related deaths.

Methods: Certain Northern European countries or regions had low death rates regardless of BCG policy. The authors assumed the consumption of foods containing salmiak (NH₄Cl) was a common and peculiar cause of the reduced COVID-19 related death rates in these countries, because NH₄Cl is a known lysosomotropic agent, which has been indicated to inhibit or prevent SARS-CoV infection. To check the possible effectiveness of salmiak consumption against COVID-19 related death, the authors used a linear regression model with the death rate as the dependent variable and BCG-policy and salmiak consumption score as independent variables.

Results: Using least squares regression and a robust standard error algorithm, the authors found a significant effect exerted by the independent variables (P < 0.0005 for BCG and P = 0.001 for salmiak). Salmiak score alone was significant (P = 0.016) when using least squares regression with robust error algorithm. 

Conclusions: The results seem to confirm an association between BCG-positive vaccination policy and salmiak consumption, and lower death rates from COVID-19. Implementing BCG vaccination policy and fortification of foods with salmiak (NH₄Cl) may have a significant impact on the control of SARS-CoV epidemic.