Passive Antibodies Against COVID-19 With EVUSHELD in Vaccine Non-responsive CLL

Inclusion Criteria: 1. Have a diagnosis of CLL according to international working group CLL criteria 2. Treatment-naïve, post treatment or on-treatment for CLL 3. Male or female ≥ 18 years of age on day of signing informed consent 4. Weight ≥ 40 kg at the screening 5. Have received at least 2 standard of care SARS-CoV-2 vaccines within the last 18 months prior to enrolment. These vaccines may include all vaccines given in Canada since the beginning of the pandemic including: Pfizer BNT162b2 (COMIRNATY®), Moderna mRNA-1273 (SPIKEVAX®), and Astra Zeneca AZD1222 (Vaxzevria®) 6. Last SARS-CoV-2 vaccination ≥28 days ago and no more than 18 months ago. 7. Participants must have a demonstrated absent or suboptimal response to standard of care SARS-CoV-2 vaccinations on screening bloodwork and will be prioritized for this study as they are deemed to be at higher risk of serious COVID-19 infection. 8. Have a performance status of 0-2 on the ECOG Performance Scale. 9. Have adequate organ function laboratory values, anytime during the screening period 10. Have a life expectancy \> 6 months in the opinion of the referring hematologist. 11. Female subject of childbearing potential should have a negative serum pregnancy test prior to receiving study medication (study day 0). 12. Female participants of childbearing potential should be willing to use 2 highly effective methods of birth control or be surgically sterile, or abstain from heterosexual activity for the duration of the study (after signing consent) to prevent pregnancy. Participants of childbearing potential are those who have not been surgically sterilized or have not been free from menses for \> 1 year. 13. Male participants should be surgically sterile or agree to use a highly effective method of contraception for the duration of the study (after signing consent) to prevent pregnancy in their partner. 14. Participants must agree to abstain from donating blood or plasma from the time of informed consent and for one year 15. Able and willing to provide signed informed consent for the trial 16. Ability to comply with protocol requirements. Exclusion Criteria: 1. Signs and symptoms consistent with symptomatic COVID-19 illness within 30 days of consent. 2. Prior (within 30 days), current, or planned use of any of COVID-19 convalescent plasma, other monoclonal antibodies against SARS-CoV-2 or any COVID-19 treatment, or if clinically indicated as standard of care for a COVID-19 infection, should not be administered within 14 days of the EVUSHELD administration 3. Current infection requiring treatment with antibiotics or antifungals (not including prophylactic medications given with current therapy). Note: Participants completing a course of antibiotics for acute infection 7 days prior to SD0 and who do not experience a recurrence of symptoms or fever are eligible. 4. Has a known history of active TB (Bacillus Tuberculosis) 5. Has known psychiatric or substance abuse disorders that would interfere with adherence with the requirements of the trial. 6. Previous hypersensitivity reaction following administration of a monoclonal antibody 7. Currently pregnant, lactating or breast feeding 8. Is currently participating and receiving study therapy or has participated in a study of an investigational agent and received study therapy or used an investigational device within 21 days of treatment (SD0). 9. Receive a COVID-19 booster shot within 90 days of EVUSHELD administration 10. Known history of allergy to any component of the study drug formulation or its excipients 11. History of clinically significant bleeding disorder, or prior history of significant bleeding or bruising following IV infusions or venipuncture. 12. Any other significant disease, disorder, or finding that may; significantly increase the risk to the participant because of participation in the study; affect the ability of the subject to participate in the study; or impair interpretation of the study data. 13. Blood drawn in excess of a total of 450 mL (1 unit) for any reason within 30 days prior to enrollment.