The purpose of the study is to describe the rate of occurrence of clinical diagnosis of acute respiratory infection (an infection that affects normal breathing) and different types of respiratory pathogens (harmful organisms) of new respiratory infections in a population at high risk for severe illness.

Inclusion Criteria:

• Must sign an informed consent form (ICF) indicating understanding the purpose, procedures, and potential risks and benefits of the study, and is willing to participate in the study
• Participants at high risk for severe respiratory infections due to their immune-suppressive status and who fit in one or more of the following categories: a) Participants with hematologic malignancy (HM) including, but not limited to, acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), acute lymphoblastic leukemia (ALL), multiple myeloma (MM): i) Newly diagnosed, within 6 months of treatment initiation; including anticipation of cytotoxic and immunomodulatory therapy such as chimeric antigen receptor T (CAR-T) ii) Hematologic relapse within 6 months from anticipating treatment initiation for relapse iii) Participants with a history of HM who have maintained the immunosuppressive status in the opinion of the investigator and after consultation with the sponsor (that is, study responsible physician or scientists) b) Participants with a history of HM who have received hematopoietic cell transplant (HCT) within 1 year for autologous recipients or within 3 years for allogeneic recipients. c) Participants with a non-HM who have received HCT within 1 year for autologous recipients or within 3 years for allogeneic recipients. This can include, but is not limited to, participants who have received HCT due to lymphoproliferative disorders, solid tumors, primary immunodeficiency, bone marrow failure syndromes, hemoglobinopathies, sickle cell disease, or autoimmune disorders. d) Participants who have developed chronic graft vs host disease (GVHD) after HCT and are currently on immunosuppressive therapy
• Must be able to read, understand, and complete questionnaires
• Must be willing and able to connect current electronic health records from one or more providers

Exclusion Criteria:

• Has a clinical condition other than those specified in inclusion criterion 3 which, in the opinion of the investigator, could prevent, confound, or limit the protocol-specified assessments (for example, asthma and allergies)
• Is, in the opinion of the investigator, unlikely to adhere to the requirements of the study or is unlikely to complete the full course of observation
• Cannot communicate reliably with the investigator
• Has moderate-severe allergies that add complexity to the assessment of acute respiratory infection (ARI) episode
• Is currently enrolled in an interventional study that could interfere with the assessment of respiratory viral dynamics

Participants at high risk for severe respiratory infections due to their immune-suppressive status.