Assessing the efficacy of mitigation strategies on the COVID-19 outbreak

We use daily data from 135 countries on each continent to study the governmental responses to COVID-19 during the first two years of the pandemic. By identifying four main strategies of governments to contain the COVID-19 pandemic, we evaluate the effect of each strategy with and without the use of vaccines. Even though the most stringent lockdown strategy is best for reducing new cases, a strategy based on tracing and testing is the only one capable of reducing new cases, new deaths, and the reproduction rate throughout the two-year period. Vaccines drastically reduced deaths and weakened the effects of mitigation strategies on new cases and the reproduction rate. Our results indicate that the best policy to defeat the effects of a pandemic like COVID-19 is to implement a strategy capable of detecting and isolating the virus without imposing broad restrictions on mobility.