Inclusion Criteria:  Above the age of 18 Known diagnosis of any malignancy- either active or completed therapy Underwent an in-person encounter at a study facility during the study period Have a negative SARS-CoV-2 spike IgG at least 14 days after the second dose of the mRNA-based vaccines (Moderna or Pfizer/BioNTech) or 28 days after a single dose of the adenovirus-based Johnson & Johnson vaccine.  Exclusion Criteria:  Patients who have had a serious adverse reaction to any prior COVID-19 vaccines resulting in emergency room visit or hospitalization, had events related to myocarditis, thrombosis and thrombocytopenia syndrome or anaphylaxis to any prior dose of the COVID-19 vaccines. Patients who have had a documented COVID-19 infection in the 90 days prior to starting the study