At the beginning of 2020, the COVID-19 epidemic outbroke. While decisively taking measures such as cutting off the channels of transmission and joint prevention and control mechanism, the Chinese government achieved important achievements in the national battle against the epidemic. Meanwhile, the COVID-19 epidemic continues to spread in other countries such as Europe and the United States, which exposes the loopholes in epidemic prevention and control in some countries. Especially, what kind of external prevention measures did those governments take in the early stages of the epidemic? Were these external prevention measures effective? Were the internal control measures taken by some governments appropriate? Moreover, was strict external prevention and lax internal control the reason for the worsening of the epidemic situation in many countries? These questions need to be answered urgently.

This paper summarizes external prevention and internal control measures taken by countries in the early stages of the epidemic. Furthermore, we evaluate the effect of external prevention, and compare internal control measures around the world. Empirical results show that from the perspective of external prevention, many countries immediately implemented a variety of entry restriction policies to respond to the COVID-19 epidemic. From the perspective of internal control, we construct an indicator reflecting the strictness of internal control based on the Google search index, which shows that the internal control measures in the early stage of the epidemic were quite different worldwide. Compared with countries taking lax external prevention measures, internal control measures were relatively lax for countries taking strict external prevention measures. Specifically, for countries taking strict external prevention measures, the government and people not only paid little attention to the COVID-19 epidemic, but also took insufficient measures and efforts to keep social distancing. These empirical evidences reveal that at the beginning of the epidemic, the government and people did not pay enough attention to the epidemic, and hoped to keep the virus out of the country through the entry restriction policy, but the internal control is weak. Precious time won by China’s active fight against the epidemic has not been utilized by those countries, which led to the worsening of the epidemic situation.

This paper is helpful to understand the cause of the spread of the COVID-19 epidemic worldwide, and it has clear policy implications to further optimize epidemic prevention and control. First, it is necessary to establish a coordination and communication mechanism based on cooperation and strengthen domestic epidemic control. Second, identifying the virus’s origin is a serious scientific issue. It is up to scientists to research and draw evidence-based conclusions, and we should adhere to scientific principles and avoid politicizing it.