Rehabilitation has been identified by the World Health Organization (WHO) as an essential health strategy, alongside promotion, prevention, treatment, and palliative care. For the WHO, rehabilitation is a core component of universal health coverage and a central target of the United Nations Sustainable Development Goal 3: Ensure healthy lives and promote well-being for all at all ages. Rehabilitation focuses on the overall functioning of the whole person, including comorbidities. Consequently, rehabilitation of individuals who have experienced COVID-19 must consider not only the consequences of the disease but also the effects of treatments applied during the acute phase. For the WHO, functioning (the target of rehabilitation) is a key indicator of health, alongside mortality and morbidity, capturing the impact of diseases and injuries on body functions, human activities and participation. Rehabilitation inherently serves to reduce disability, with broad health, social, and economic impacts.

This Special Collection is the result of collaboration within Cochrane Rehabilitation, with rigorous involvement from stakeholders: the Steering Committee of the REH-COVER (Rehabilitation COVID-19 Evidence-based Response) action and the Cochrane Rehabilitation Advisory Board. The agreed list of relevant conditions is the product of a structured prioritization process for identifying the list of conditions, and subsequently review inclusion, except post-traumatic stress disorder (PTSD), for which Cochrane Mental Health and Neuroscience was consulted.

The long-term effects of surviving COVID-19 have
become a new focus of attention for clinicians and
researchers. This focus has been driven partly by concerns
about late ill-effects of a previously unknown virus, but
recognised generic patterns of chronic disease after
critical illness also exist. These patterns are termed PICS,
an acronym both for post-intensive care syndrome and
for persistent inflammation, immunosuppression, and
catabolism syndrome. We recommend unifying post-
COVID-19 research aims with those of PICS research
and propose a novel approach to its management by
repurposing drugs that are approved, inexpensive, and
safe.

As a result of the current global health crisis, many more people than usual are having serious medical experiences. These include admissions to hospital with breathing difficulties, or transfers to critical care (intensive care) units. A significant proportion of these people will go on to develop symptoms of post-traumatic stress disorder (PTSD).