Does the BCG Vaccine Protect Against Coronavirus? Applying an Economist’s Toolkit to a Medical Question

As COVID-19 has spread across the globe, there is an intense search for treatments and vaccines, with numerous trials running in multiple countries. Several observers and prominent news outlets have noticed that countries still administering an old vaccine against tuberculosis—the Bacillus Calmette-Guerin (BCG) vaccine—have had fewer coronavirus cases and fewer deaths per capita in the early stages of the outbreak. But is that correlation really strong evidence that the BCG vaccine provides some defense against COVID-19? In this post, we look at the incidence of coronavirus cases along the former border between East and West Germany, using econometric techniques to investigate whether historical differences in vaccination policies account for the lower level of infection in the former East.