61 The extent to which the risks and evolving effe f cts of health epidemics impact our business and our clinical development and regulatory r effo f rts will depend on future developments that are highly uncertain and cannot be predicted with confid f ence, such as the ultimate duration and severity of the pandemic, government actions, such as travel restrictions, quarantines and social distancing requirements, business closures or business disrupt r ions and the effe f ctiveness of actions taken in the United States and in other countries to contain and treat the disease, including the effe f ctiveness and timing of vaccine programs in the United States and worldwide. Health epidemics may also have the effe f ct of heightening many of the other risks described in this “Risk Factors” section.