This article discusses the United States' abandonment of its traditional role as world leader in health system during a period of severe international crises and its impact on the international security system. Attention is paid both to the country's specific foreign policy actions, which indicate a departure from the traditional for the U.S. “grand strategy” paradigm, and to domestic factors caused by the devastating effects of the pandemic. The U.S. response to the coronavirus pandemic is compared to how it has handled health threats in the past. The difference in approach may be explained by the features of the current administration's foreign policy, which is characterized by isolationism and distrust in international organizations, but there may be other factors related to the characteristics of the international system today. Unfortunately, the length of the thesis does not allow for a broader examination of the problem of world leadership during the COVID-19 pandemic. In particular, the question of the possible replacement of the United States by another international actor, such as China, is taken out of the scope of the current discussion.