COVID-19 is quickly spreading around the world and carries along with it a significant threat to public health. This study sought to apply meta-analysis to more accurately estimate the basic reproduction number (R0) because prior estimates of R0 have a broad range from 1.95 to 6.47 in the existing literature. Utilizing meta-analysis techniques, we can determine a more robust estimation of R0, which is substantially larger than that provided by the World Health Organization (WHO). A susceptible-Infectious-removed (SIR) model for the new infection cases based on R0 from meta analysis is proposed to estimate the effective reproduction number Rt. The curves of estimated Rt values over time can illustrate that the isolation measures enforced in China and South Korea were substantially more effective in controlling COVID-19 compared to the measures enacted early in both Italy and the United States. Finally, we present the daily standardized infection cases per million population over time across countries, which is a good index to indicate the effectiveness of isolation measures on the prevention of COVID-19. This standardized infection case determines whether the current infection severity status is out of range of the national health capacity to care for patients.