The demand on front-line healthcare workers in hospital and long-term care facilities has become more intense due to the COVID-19 pandemic. Prior to the pandemic, there were already challenges due to sickness absence (SA) in healthcare and this is likely to increase. However, the increase may not be entirely related to the virus. It may also be due to underlying issues, particularly with staff shortages, which existed before COVID-19. This paper highlights these underlying issues. We also present a conceptual framework addressing SA in healthcare, which is based on extensive meta-analysis and qualitative research.