This review highlights the relationship among sleep duration, sleep quality, the immune system, and SARS-CoV‑2 infection. Short and/or poor sleep may have an impact on the development as well as the course of an infection. Similarly, SARS-CoV‑2 infection as well as pandemic-related circumstances may negatively affect sleep. In particular, sleep quality decreases. The pandemic thus has the potential to initiate, exacerbate, and/or maintain sleep disorders. These findings are relevant because only sufficient and restful sleep can strengthen and have a protective effect on the immune system with respect to infection and its course. Therefore, the pandemic poses another challenge for sleep medicine, and at the same time offers an opportunity to communicate the importance of sleep for health and disease course.