The study ended earlier than anticipated due to slow accrual.

This study evaluates the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). CLL and SLL are types of blood cancer that begin in cells of the immune system. CLL/SLL and the medications used to treat these conditions may change the way vaccines work in a patient's body. The purpose of this study is to find out if patients with CLL/SLL make antibodies, or have an immune response, to the SARS-CoV-2 vaccines. Information gained from this study may help researchers better understand how effective the vaccines work in preventing COVID-19 (coronavirus disease 2019) in patients with CLL and SLL.

OUTLINE:

For patients who have not been vaccinated at the time of enrollment, they will undergo collection of blood samples prior to the first vaccine dose, just before the second vaccine dose, and then at 1, 6, and 12 months after the second vaccine dose. Patients' medical records are also reviewed.

For patients enrolled after vaccination, they will undergo collection of blood samples at 1-4, 6, and 12 months after completing the vaccination series. Patients who receive booster dose also undergo collection of blood samples at 1, 6, and 12 months post final booster dose.

After completion of study, patients are followed up every 6 months for 2 years.

Inclusion Criteria:

• Age >= 18 years
• A diagnosis of chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL)
• Willing and able to participate in all required evaluations and procedures in this study

Exclusion Criteria:

• Any evidence of prior SARS-CoV-2/COVID19 infection

Patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) who receive a SARS-CoV-2 vaccine