Correlation between universal BCG vaccination policy and reduced morbidity and mortality for COVID-19: an epidemiological study

Aaron Miller; Mac Josh Reandelar; Kimberly Fasciglione; Violeta Roumenova; Yan Li; Gonzalo H Otazu

Initially, we compared countries that never had in place a universal BCG vaccination policy (Italy, USA, Lebanon, Nederland, and Belgium), with countries that have a current universal BCG vaccination policy. We included only countries with more than 1 million inhabitants. The mortality rate might be influenced by multiple factors including a country's standard of medical care. In order to account for that, we classified countries according to their GNI per capita in 2018 using the World Bank data (https://datahelpdesk.worldbank.org/knowledgebase/articles/906519-worldbank-country-and-lending-groups). Countries were divided in three categories: low income (L) with an annual income of 1,025 dollars or less, lower middle income with an income between 1,026 and 3,995 dollars, and middle high and high income countries, which included countries with annual incomes over 3,996 dollars. In order to determine if BCG vaccination was protective for COVID-19 infections, we used the number of deaths per million inhabitants per country attributed to COVID-19 (see attached table) . Most of the countries with low-income levels (17/18) reported zero deaths attributed to COVID-19 and have universal BCG policies in place consistent with a protective role of BCG vaccination. However, this might be because of underreporting and we have excluded them from the analysis. Middle high and high-income countries that have a current universal BCG policy (55 countries) had 0.78± 0.40 (mean±s.e.m) deaths per million people (see Figure 1 ). In contrast, middle high and high income countries that never had a universal BCG policy (5 countries) had a larger mortality rate, with 16.39 ± 7.33 deaths per million people. This difference between countries was highly significant (p=8.64e-04, Wilcoxon rank sum test).