This paper is interested to introduce a new macroeconomic indicator to evaluate the impact of any massive pandemic such as COVID-19 on the world economy performance in the short run (1 year) and long run (10 years). The new macroeconomic indicator is entitled “The Economic Uncontrolled Desgrowth from COVID-19 (-δCOVID-19).” In fact, the new macroeconomic indicator assumes that always COVID-19 is going to be the major factor to generate a large economic leakage on the final GDP formation anytime and anywhere. Additionally, the same paper is willing to evaluate two post-COVID-19 possible scenarios. The first scenario: if COVID-19 is going to generate a short economic recession, then the world economy gross domestic product can delay between two and three years. The second scenario: if COVID-19 is going to produce a large economic depression, then the world economy gross domestic product can take easily between five and ten years such as the case of the world great depression of 1928. From now, the economists need to decide between two possible choices to solve these two types of economic crisis (recession or depression): The first choice is the uses of the classical economic policies –fiscal or monetary- from past experiences (Keynesians and Monetarists). The second choice is the creation of new and innovative polices approaches to reduce the COVID-19 damage under the support of new theoretical and methodological approaches.