The United States is experiencing a rise in respiratory illnesses, commonly referred to as a “tripledemic,” involving COVID-19, influenza (flu), and respiratory syncytial virus (RSV), according to the Centers for Disease Control and Prevention (CDC).

Shares of vaccine makers moved higher early Monday following a CDC report that the U.S. was seeing a significant uptick in acute respiratory illness due to higher rates of seasonal influenza, COVID-19 and RSV.