In order to be eligible to participate in this study, an individual must meet all of the following criteria:
1. Obtain a signed and dated informed consent form from participant
2. State their willingness to comply with all study procedures and availability for the duration of the study
3. Male or female, aged ≥18 years old
4. Meet the following criteria for "Post-COVID Condition" or Long COVID:
1. 6-months prior, documented SARS-CoV-2 infection
2. Cognitive impairment as defined by having at least 20% positive (worse or much worse) items on the ECOG assessment
3. Neurocognitive symptoms must have been present for at least 60 days prior to screening. Symptoms that wax and wane must have been initially present at least 60 days prior to screening.
5. Ability to take oral medication and be willing to adhere to the baricitinib regimen
6. Females of childbearing potential must agree to either abstinence or use at least one acceptable method of contraception from the time of screening though at least 28 days after the end of the study intervention period. Note: Acceptable methods include barrier contraceptives (condoms or diaphragm) with spermicide, intrauterine devices (IUDs), hormonal contraceptives, oral contraceptive pills, and surgical sterilization.
Exclusion Criteria:
An individual who meets any of the following criteria will be excluded from participation in this study:
1. Pre-existing cognitive impairment not exacerbated by acute COVID as determined by study physicians after thorough review of participant's history and medical records
2. Current use of baricitinib or other disease-modifying antirheumatic drug (DMARDs)
3. Known allergic reactions to components of the baricitinib
4. Have ever been randomized in this study or any other study investigating baricitinib
5. Positive SARS-CoV-2 PCR or rapid Antigen test in the past 14 days
6. Pregnancy or breastfeeding
7. Any history of venous thromboembolism ever
8. History of malignancy or lymphoproliferative disorder
9. Renal dysfunction with estimated glomerular filtration rate of \< 30 mL/min/1.73m2
10. Absolute Neutrophil Count (ANC) \<1200 cells/mm3
11. History or evidence of severe or end-stage liver disease (e.g. bilirubin ≥1.5x or AST/ALT \>2x normal).
12. Positive Hepatitis B surface antibody, antigen or core antibody, or Positive Hepatitis C RNR or antigen
13. Positive HIV 4th generation (antibody/antigen) ELISA test
14. Have had symptomatic herpes zoster infection within 3 months prior to study entry or have a history of disseminated/complicated herpes zoster or herpes simplex infection
15. History of latent (diagnosed with Quantiferon testing) or active tuberculosis
16. History of a current or recent (\< 30 days from screening) clinically significant viral, bacterial, fungal, or parasitic infection
17. History of chronic alcohol abuse, Intravenous (IV) drug abuse, or other illicit drug abuse within the 2 years prior to study entry
18. Are immunocompromised and, in the opinion of the investigator, are at an unacceptable risk for participating in the study
19. Treatment with another investigational drug or other intervention \< 30 days of study enrollment
20. Are unable or unwilling to make themselves available for the duration of the study and/or are unwilling to follow study restrictions/procedures
21. Severe cognitive, physical, or psychological disability that would prevent participation in the study
