The coronavirus is one of the most unprecedented pandemics in recent decades. Countries have been struggling to identify the appropriate policies to prevent COVID-19 spread efficiently. As coronavirus case and death numbers fluctuated among countries in the past two years, questions of which policies are most cost-efficient and effective in preventing coronavirus spread have yet to be answered. There are no worldwide agreed guidelines to follow, to the author's best knowledge. Countries are prone to making policy and implementation errors that could cost lives and cause tremendous economic loss. Although much research on COVID-19 has been done and many focused on policy effectiveness, few focused on the cost-efficiency and effectiveness of COVID-19 policies. This research identifies the most Cost-Efficient and Effective Set of COVID-19 Policies to Reduce Monthly COVID-19 Case Increase Rates through a quantitative, big-data-driven, and machine-learning enabled approach. The research collected and analyzed 13 COVID-19 policies and associated daily COVID-19 case numbers across 180 countries from January 2020 to June 2021, developed Policy Cost Model, defined Policy Efficiency and Effectiveness Index, and developed a Fully-Automated Best Policy Group Finder Python Program to find the most cost efficient and effective policy group. This research found that 1) Before Vaccinations are available, the most cost-efficient and effective policy group includes Facial Covering, Testing Policy, and Contact Tracing. Its cost-efficiency is a 1% monthly case decrease rate per billion of dollars spent. Its effectiveness is a 37% monthly case decrease rate. It is 1474 times more cost-efficient, 11 times more effective, and costs around $5336.83 Billion less than implementing all 12 common COVID-19 policies as the U.S. and many other countries did before vaccinations were available; 2) After Vaccinations are available, the most cost-efficient and effective policy group includes Facial Coverings, Contact Tracing, and Vaccinations. Its cost-efficiency is a 2.7% monthly case decrease rate per billion of dollars spent. Its effectiveness is a 52% monthly case decrease rate. It is 3835 times more cost-efficient, 21.5 times more effective, and costs around $5350 Billion less than implementing all 13 common COVID-19 policies as the U.S. and many other countries did. The research results will help countries, especially underdeveloped ones with very limited budgets, to identify and implement the most cost-efficient and effective policies so they can spend much less but reduce monthly cases much more.

The authors have declared no competing interest.

This study did not receive any funding.

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All data produced in the present study are available upon reasonable request to the authors.