This study delves into the financial aspect of the deep economic destruction caused by the COVID-19 pandemic globally, focusing on the healthcare services, medical device manufacturers and pharmaceutical companies operating in the healthcare industry. The results of the study were remarkable, suggesting that the healthcare sector as a whole has demonstrated a consistent sensitivity to negative news or shocks both before and during the COVID-19 pandemic. Additionally, some companies within the medical device and pharmaceutical sectors have shown changes in their sensitivity to positive and negative news after the pandemic. In light of this, the study recommends that risk management units and decision makers of the companies mentioned in the findings of this study should strengthen their financial immunities in the face of potential shocks. Furthermore, the study extensively examines the non-linear characteristics of stock returns, providing a special report for each company, where the "fat tail" characteristics of the company's shares were evaluated within the framework of alpha stable distribution. The results of this study provide crucial insights for companies.