Inclusion Criteria:

• Willing to receive COVID-19 vaccination as per standard of care or has already received one or both COVID-19 vaccine injections as long as it has not been longer than three months since their second injection (or the only injection if they receive the types of COVID-19 vaccines that do not require the second injection).
• Willing and able to provide research blood samples.
• Capable of providing valid informed consent.
• For cancer patient cohort:
  • Male or female age ≥ 18 years;
  • Histologically confirmed solid malignancy on or will be starting on systemic cytotoxic chemotherapy.
• For healthy individual cohort:
  1.  
  • Male or female age ≥ 18 years;
  • No history of active malignancy ≤ 3 years.
  • EXCEPTIONS: Adequately treated non-melanotic skin cancer (adequate wound healing is required prior to study entry) or carcinoma-in-situ of the cervix.
  • NOTE: If there is a history of prior solid tumor malignancy, it must have been treated curatively with no evidence of recurrence ≤ 3 years.

Exclusion Criteria:

• Immunocompromised patients including patients known to be HIV positive or those on immunosuppressive therapy other than chemotherapy in the judgment of the investigator.