This randomized controlled trial (RCT) with 160 patients suffering from fatigue after COVID-19 infection aims to investigate the effectiveness of the unguided digital therapeutic vimida for reducing post-COVID-19 fatigue. Inclusion criteria are: male, female or non-binary, age ≥18 years, diagnosis of post-COVID-19 fatigue, ≥3 months since the last infection with COVID-19, fatigue severity score (cut-off) of ≥ 16 on the Chalder Fatigue Scale (CFQ-11), consent to participation, and sufficient German language skills. Exclusion criteria are a known psychiatric or somatic condition that can explain the fatigue and current participation in a multidisciplinary rehabilitation program aimed to ameliorate the consequences of COVID-19.

Patients will be randomized and allocated to either an intervention group, in which they will receive access to vimida in addition to treatment as usual (TAU; n=80), or to a control group, in which they will receive access to TAU only (n=80).

The primary endpoint will be fatigue symptoms with three months post-allocation (T1) being the primary time point for assessment of effectiveness. Six months post-allocation (T2) will be used as follow-up assessment of endpoints. Secondary endpoints will be depressive symptoms, mental health-related quality of life, work/social functioning, somatic symptoms, and anxiety symptoms.

Inclusion Criteria:

• male, female or non-binary
• age ≥ 18
• diagnosis of post-COVID-19 fatigue (ICD-10 U08.9, or U09.9 in conjunction with G93.3), secured via a telemedical visit
• ≥ 3 months since COVID-19 infection that preceded fatigue symptoms
• elevated levels of fatigue: cut-off of ≥ 16 on the CFQ-11
• consent to participation
• sufficient knowledge of the German language

Exclusion Criteria:

• known somatic or psychiatric condition that can explain the fatigue (e.g., cancer, multiple sclerosis, severe depression)
• current participation in a multidisciplinary rehabilitation program aimed at ameliorating the consequences of COVID-19