This study will test if a medicine called baricitinib, compared to a placebo (a pill with no medicine), can help with Long COVID symptoms. Long COVID is when people have problems like memory trouble, tiredness, or trouble breathing, even after recovering from COVID-19. The study will check if baricitinib helps improve brain functions, physical activities, and overall life quality for these patients.

To join, you need to be at least 18 years old and have had COVID-19 at least 6 months ago. You must also have symptoms like fatigue or "brain fog" that started after COVID-19 and have lasted for at least 6 months. You cannot join if you have other serious health conditions, are pregnant, or taking certain medicines.

• The study will include 550 participants divided into two groups (500 and 50).
• Participants will receive either baricitinib or placebo.
• Symptoms and improvements will be tracked over time.

This trial seeks to find a treatment for Long COVID, which has no current effective interventions. Participants should consider their health conditions and commitments before joining.