• Hospitalized with COVID-19 pneumonia confirmed per WHO criteria (including a positive PCR of any specimen; e.g., respiratory, blood, urine, stool, other bodily fluid) and evidenced by chest X-ray or CT scan
• Peripheral capillary oxygen saturation (SpO2) ≤93% (on room air or supplemental oxygen) or partial pressure of oxygen (PaO2)/fraction of inspired oxygen (FiO2) ≤300 millimetres of mercury (mmHg) or requiring supplemental oxygen to maintain SpO2 >93% or requirement for supplemental oxygen to maintain SpO2 at an acceptable level per local standard of care
• Pregnant or breastfeeding, or positive pregnancy test at screening
• Any serious medical condition or abnormality of clinical laboratory tests that, in the investigator's judgment, precludes the patient's safe participation in and completion of the study
• In the opinion of the investigator, progression to death is imminent and inevitable within the next 24 hours, irrespective of the provision of treatments
• Participating in another clinical drug trial
• Treatment with investigational therapy (other than for COVID-19) within 5 half-lives or 30 days (whichever is longer) prior to initiation of study drug
• Use of Janus kinase (JAK) inhibitor within 30 days or 5 drug elimination half-lives (whichever is longer) prior to screening
• Have received high-dose systemic corticosteroids (≥1 mg/kg/day methylprednisolone or equivalent) within 72 hours prior to Day 1
• Known HIV infection with CD4 <200 cells/microlitre (uL) or <14% of all lymphocytes
• ALT or AST >10 times the upper limit of normal (ULN) detected at screening
• History of anaplastic large-cell lymphoma or mantle-cell lymphoma
• History of cancer within the previous 5 years unless it has been adequately treated and considered cured or remission-free in the investigator's judgment
• Clinical evidence of active or unstable cardiovascular disease (e.g., acute myocardial ischemia or decompensated heart failure), as determined by investigator assessment, ECG, laboratory assessment, or echocardiographic data
• History of moderate or severe allergic, anaphylactic, or anaphylactoid reactions or hypersensitivity to any component of study treatment

• ≥ 18 years of age
• Hospitalized for COVID-19
• Enrolled within 72 hours of hospital admittance or 72 hours of positive COVID test
• Expected to require hospitalization for > 72 hours
• Imminent death
• Requirement for chronic mechanical ventilation via tracheostomy prior to hospitalization
• Pregnancy
• Based on a recommendation from the ACTIV4 DSMB on December 19, 2020, enrollment of patients requiring ICU level of care into the therapeutic anti-coagulation arm was stopped due to meeting a futility threshold and a potential for harm for this sub-group could not be excluded. Enrollment continues for moderately ill hospitalized COVID-19 patients.

• REGISTRATION TO SURGERY (ARM S)
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
• Patients must have newly diagnosed, histologically or cytologically confirmed squamous cell carcinoma or undifferentiated carcinoma of the oropharynx; patients must have been determined to have resectable oropharyngeal disease; patients with primary tumor or nodal metastasis fixed to the carotid artery, skull base or cervical spine are not eligible
• Patients must have American Joint Committee on Cancer (AJCC) TNM tumor stage III, IV a, or IV b (with no evidence of distant metastases) as determined by imaging studies (performed < 4 weeks prior to pre-registration) and complete head and neck exam; the following imaging is required: computed tomography (CT) scan with IV contrast or magnetic resonance imaging (MRI)
• Patients must have biopsy-proven cyclin-dependent kinase inhibitor 2A (p16)+ oropharynx cancer; the histologic evidence of invasive squamous cell carcinoma may have been obtained from the primary tumor or metastatic lymph node; it is required that patients have nodal stage N1-N2b confirmed by clinical or radiographic methods (clinically N0 patients are not eligible)
• Carcinoma of the oropharynx associated with HPV as determined by p16 protein expression using immunohistochemistry (IHC) performed by a Clinical Laboratory Improvement Amendments (CLIA) approved laboratory; using p16 antibody obtained from Roche mtm laboratories AG (CINtec, clone E6H4) is recommended
• No prior radiation above the clavicles
• Patients with a history of a curatively treated malignancy must be disease-free for at least two years except for carcinoma in situ of cervix and/or non-melanomatous skin cancer
• Patients with the following within the last 6 months prior to pre-registration must be evaluated by a cardiologist and/or neurologist prior to entry into the study
• Patients must not have evidence of extensive or "matted/fixed" pathologic adenopathy on preoperative imaging
• Absolute neutrophil count >= 1,500/mm^3
• Platelets >= 100,000/mm^3
• Total bilirubin =< the upper limit of normal (ULN)
• Calculated creatinine clearance must be > 60 ml/min using the Cockcroft-Gault formula
• Women must not be pregnant or breast-feeding due to the teratogenicity of chemotherapy; all females of childbearing potential must have a blood test or urine study within 2 weeks prior to registration to rule out pregnancy; a female of childbearing potential is any woman, regardless of sexual orientation or whether they have undergone tubal ligation, who meets the following criteria: has not undergone a hysterectomy or bilateral oophorectomy; or has not been naturally postmenopausal for at least 24 consecutive months (i.e., has had menses at any time in the preceding 24 consecutive months)
• Patient must not have an intercurrent illness likely to interfere with protocol therapy or prevent surgical resection
• Patients must not have uncontrolled diabetes, uncontrolled infection despite antibiotics or uncontrolled hypertension within 30 days prior to pre-registration
• REGISTRATION/RANDOMIZATION TO STEP 2
•ARMS A, B, C AND D AND REGISTRATION TO STEP 3
• Histopathologic assessment of surgical pathology must include examination for perineural invasion (PNI) and lymphovascular invasion (LVI) and reported as absent or present; the absence or presence of extracapsular extension (ECE) requires gross and microscopic assessment and is defined to be:
• Absent (negative or nodal metastasis with smooth/rounded leading edge confined to thickened capsule/pseudocapsule),
• Present
•minimal (tumor extends =< 1 mm beyond the lymph node capsule), or
• Present
•extensive (gross, tumor extends > 1 mm beyond the lymph node capsule (includes soft tissue metastasis)
• Patients must have ECOG performance status 0 or 1
• Patient must be registered/randomized within 5-7 weeks following surgery
• Women of childbearing potential and sexually active males are strongly advised to use an accepted and effective method of contraception

1. Birth to <18 years of age; AND 2. Positive nucleic acid test for SARS-CoV-2 within the past 7 days; AND 3. Hospitalized, <72 hours post-admission; AND 4. One or more signs and/or symptoms of COVID-19 illness within the past 72 hours, as follows: 1. Cough; OR 2. Fever (oral temperature >100.4°F/38°C); OR 3. Chest pain; OR 4. Shortness of breath; OR 5. Myalgia; OR 6. Acute unexplained loss of smell or taste; OR 7. New/increased supplemental oxygen requirement; OR 8. Acute respiratory failure requiring non-invasive or invasive ventilation; OR 9. Encephalitis. An individual who meets any of the following criteria will be excluded from participation in this study: 1. Receiving therapeutic anticoagulation for treatment of a thromboembolic event diagnosed within the past 12 weeks; OR 2. Clinical-relevant bleeding (see criteria under Primary Outcome, below) within the past 72 hours; OR 3. Platelet count <50,000/µL within the past 24 hours; OR 4. Prothrombin time (PT) ≥2 seconds above the upper limit of age-appropriate local reference range within the past 24 hours; OR 5. Activated partial thromboplastin time (aPTT) ≥4 seconds above the upper limit of age-appropriate local reference range within the past 24 hours; OR 6. Fibrinogen level <75 mg/dL; OR 7. Severe renal impairment, as defined by estimated glomerular filtration rate (eGFR) <31 mL/min/ 1.73 m2, as calculated by the Schwartz formula; OR 8. Parent or legally authorized representative unwilling to provide informed consent for patient participation.

• Biopsy proven (from primary lesion and/or lymph nodes) diagnosis of cancer of the nasopharynx
• Patients must have detectable pretreatment plasma EBV DNA, determined by the central lab prior to Step 2 registration
• Stage II-IVB disease (American Joint Committee on Cancer [AJCC], 7th edition [ed.]) with no evidence of distant metastasis, based upon the following minimum diagnostic workup:
• History/physical examination by a Medical Oncologist or Clinical Oncologist or Radiation Oncologist or Ear, Nose, Throat specialist (ENT), which must include an endoscopic evaluation, a complete list of current medications, and assessment of weight and weight loss in the past 6 months within 21 days prior to registration
• Evaluation of tumor extent with magnetic resonance imaging (MRI) of the nasopharynx and neck within 28 days prior to registration; if MRI is medically contraindicated, obtain computed tomography (CT) scan with =< 3 mm contiguous slices with contrast and bone windows (to evaluate base of skull involvement); Note: If a treatment planning CT scan is used, it must be with =< 3 mm contiguous slices with contrast and be read by a radiologist
• To rule out distant metastasis, patients must undergo the following imaging within 28 days prior to registration:
• A CT scan with contrast of the chest, abdomen, and/or pelvis or a total body positron emission tomography (PET)/CT scan (non-contrast PET/CT is acceptable)
• A bone scan only when there is suspicion of bone metastases (a PET/CT scan can substitute for the bone scan)
• Zubrod performance status 0-1 within 21 days prior to registration
• Absolute neutrophil count (ANC) >= 1,500 cells/mm^3
• Platelets >= 100,000 cells/mm^3
• Hemoglobin >= 8.0 g/dl (Note: the use of transfusion or other intervention to achieve hemoglobin [Hgb] >= 8.0 g/dl is acceptable)
• Total bilirubin =< 1.5 x institutional upper limit of normal (ULN)
• Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) =< 1.5 x institutional ULN
• Alkaline phosphatase =< 1.5 x institutional ULN
• Serum creatinine =< 1.5 mg/dl or calculated creatinine clearance (CC) >= 50 ml/min determined by 24-hour urine collection or estimated by Cockcroft-Gault formula
• Negative serum pregnancy test within 14 days prior to registration for women of childbearing potential
• Women of childbearing potential and male participants who are sexually active must agree to use a medically effective means of birth control throughout protocol treatment
• Patient must provide study specific informed consent prior to study entry, including the mandatory pre-treatment plasma EBV DNA assay
• Prior invasive malignancy (except node negative, non-melanomatous skin cancer) unless disease free for a minimum of 1095 days (3 years) (for example, carcinoma in situ of the breast, oral cavity, or cervix are all permissible)
• Prior systemic chemotherapy for the study cancer; note that prior chemotherapy for a different cancer is allowable; however, at least 6-weeks recovery is necessary if the last regimen included nitrosourea or mitomycin
• Prior radiotherapy to the region of the study cancer that would result in overlap of radiation therapy fields
• Patients with hearing loss assessed to be primarily sensorineural in nature, requiring a hearing aid, or intervention (i.e. interfering in a clinically significant way with activities of daily living); a conductive hearing loss that is tumor-related is allowed
• >= Grade 2 peripheral sensory neuropathy (CTCAE, v. 4.0)
• Severe, active co-morbidity, defined as follows:
• Major medical or psychiatric illness, which in the investigator's opinion would interfere with the completion of therapy and follow up or with full understanding of the risks and potential complications of the therapy
• Unstable angina and/or uncontrolled congestive heart failure within the past 6 months
• Myocardial infarction within the last 6 months
• Acute bacterial or fungal infection requiring intravenous antibiotics at the time of registration; note that patients switched from IV antibiotics and currently on oral antibiotics whose infection is assessed to be adequately treated or controlled are eligible
• Chronic obstructive pulmonary disease exacerbation or other respiratory illness requiring hospitalization or precluding study therapy within 30 days prior to registration
• Acquired immune deficiency syndrome (AIDS) based upon current Centers for Disease Control and Prevention (CDC) definition; note, however, that human immunodeficiency virus (HIV) testing is not required for entry into this protocol
• Pregnancy or women of childbearing potential and men who are sexually active and not willing/able to use medically acceptable forms of contraception
• Prior allergic reaction to the study drug(s) involved in this protocol
• Patients with undetectable pre-treatment plasma EBV DNA

• born between 1945 and 1965
• ≥ 1 outpatient visit during 12 months prior to randomization at Parkland
• no prior HCV screening (prior HCV antibody, viral load, or genotype).
• any active medical coverage
• speaks Spanish or English
• a life expectancy less than one year including end stage CHF, end stage COPD, metastatic cancer, and those who received a palliative care or hospice referral in the past year
• history of HCC.
• non-English or Spanish speakers
• no address or phone number on file

Inclusion Criteria Patients who have received any type of allogeneic transplant or who have a primary immunodeficiency disorder will be eligible if they have CMV, adenovirus, and/or EBV infection/disease with failure of treatment after 7 days of standard therapy OR if unable to tolerate standard therapy.
• Patients must meet one of the following criteria:
• Recipient of prior myeloablative or non-myeloablative allogeneic hematopoietic stem cell transplant using either bone marrow or peripheral blood stem cell or single or double cord blood within the previous 18 months, OR
• Have a diagnosed primary immunodeficiency disorder (as defined by clinical and laboratory evaluations) and not undergone HSCT.
• Treatment of the following persistent or relapsed infections despite standard therapy:
• CMV: Treatment of persistent or relapsed CMV disease or infection after standard therapy. For CMV infection, standard therapy is defined as antiviral therapy with ganciclovir, foscarnet or cidofovir for at least 14 days.
• Adenovirus: Treatment of persistent or relapsed adenovirus infection or disease despite standard therapy. Standard therapy is defined as antiviral therapy with cidofovir or brincidofovir.
• EBV: Treatment of persistent or relapsed EBV infection despite standard therapy. For EBV infection, standard therapy is defined as rituximab given at 375 mg/m2 in patients for 1-4 doses with a CD20+ tumor. Additional
• Patients with simultaneous infections with CMV, EBV and/or Adenovirus infections are eligible if one or more infection(s) is persistent or relapsed despite standard therapy as defined above. Patients with multiple infections with one or more reactivation and one or more controlled infection are eligible to enroll.
• Clinical status at enrollment that allows tapering of steroids to equal or less than 0.5 mg/kg/day prednisone (or equivalent) prior to infusion of the VST doses.
• Negative pregnancy test in female patients if applicable (childbearing potential who have received a reduced intensity conditioning regimen).
• Written informed consent and/or signed assent line from patient, parent or guardian. Exclusion Criteria
• Patients receiving ATG, Campath, Basiliximab or other immunosuppressive monoclonal antibodies targeting T-cells within 28 days of screening for enrollment.
• Patients who have received donor lymphocyte infusion (DLI) or other experimental cellular therapies within 28 days.
• Current therapy with ruxolitinib or other JAK inhibitors within the previous 3 days.
• Patients with other uncontrolled infections, defined as bacterial or fungal infections with clinical signs of worsening despite standard therapy. For bacterial infections, patients must be receiving definitive therapy and have no signs of progressing infection for 72 hours prior to enrollment. For fungal infections, patients must be receiving definitive systemic anti-fungal therapy and have no signs of progressing infection for 1 week prior to enrollment.
• Progressing infection is defined as hemodynamic instability, worsening physical signs, or radiographic findings attributable to infection. Persisting fever without other signs or symptoms will not be interpreted as progressing infection.
• Patients with active and uncontrolled relapse of malignancy (if applicable).

Sites:
• Serve a cohort of at least 100 HIV patients
• Have an Electronic Health Record (EHR)
• Agree to collaborate on implementing feasible adaptations of intervention strategies Patients:
• Patient of the site with a diagnosis of HIV
• Age 40-79 years
• ≥5% risk for CVD as calculated using the ASCVD Risk Estimator Plus
• Willing to participate
• No plans to leave the site in the next 12 months
• Proficient in either English or Spanish
• Own a cell phone with texting capabilities Clinicians:
• Physicians, Physicians Assistants, or Nurse Practitioners who provide direct HIV care to patients
• Work at a participating site
• Willing to implement the project's intervention strategies Patients:
• Currently participating in another CVD trial
• Have experienced a prior cardiac or vascular event such as myocardial infarction (MI) or cerebrovascular accident (CVA)
• Have had a CVD procedure such as installation of a stent or angioplasty
• Have peripheral vascular disease, intermittent claudication or peripheral arterial disease
• Are pregnant
• Lacks capacity to consent Clinicians: • Planning to leave the site within the next 12 months

• All "high energy" tibial plateau fractures treated operatively with plate and screw fixation.
• We define "high energy" tibial plateau fractures as patients who are either:
• Initially treated with an external fixation (with or without limited internal fixation) and treated definitively more than 3 days later after swelling has resolved.
• Any open type I, II, or IIIA fracture, regardless of timing of definitive treatment.
• Any tibial plateau fracture associated with ipsilateral leg compartment syndrome fasciotomy wounds.
• All "high energy" pilon (distal tibial plafond) fractures treated operatively with plate and screw fixation. We define "high energy" pilon fractures as patients who are either:
• Initially treated with an external fixation (with or without fibula fixation or limited internal fixation) and treated definitively more than 3 days later after swelling has resolved.
• Any open type I, II, or IIIA fracture, regardless of timing of definitive treatment.
• Any tibial pilon fracture associated with ipsilateral leg compartment syndrome fasciotomy wounds.
• Ages 18 to 80 years
• Patients may have co-existing non-tibial infection, with or without antibiotic treatment.
• Patients may have risk factors for infection including diabetes, immunosuppression from steroids or other medications, HIV, or other infections.
• Patients may have a head injury
• Patients may have a portion of the fixation (e.g. fibula fixation in pilon or percutaneous screws across a tibial plateau fracture) prior to definitive plate fixation, at the initial surgery before randomization.
• Patients may have other orthopedic and non-orthopaedic injuries.
• Patients may have pre-existing musculoskeletal injuries, be non ambulators, or have spinal cord injuries.
• Women and minorities are included
• The study injury: tibial plateau, pilon, is already infected at time of study enrollment.
• Patient speaks neither English nor Spanish.
• Patients who have already had definitive fixation prior to enrollment in the study.
• Severe problems with maintaining follow-up (e.g. patients who are homeless at the time of injury or those how are intellectually challenged without adequate family support).
• Patients with allergies, drug administration reactions, or other sensitivities to Vancomycin (such as a history of Redman's Syndrome).
• Pregnancy.
• The study injury is a type IIIB or IIIC open fracture.

• Patient must have a history of solid organ transplantation
• Patients must have biopsy-proven newly diagnosed, relapsed or refractory polymorphic or monomorphic PTLD using the World Health Organization (WHO) classification and that is:
• CD20 positive
• EBV positive by Epstein-Barr virus early ribonucleic acid (RNA) (EBER) in situ hybridization (preferred) and/or LMP immunoperoxidase staining
• There must be evaluable disease at study entry either by imaging or by serial endoscopic biopsies.
• Note: a measurable node must have an LDi (longest diameter) greater than 1.5 cm; a measurable extranodal lesion should have an LDi greater than 1.0 cm; all tumor measurements must be recorded in millimeters (or decimal fractions of centimeters)
• Patients must be considered medically refractory to decreased immunosuppression (50% or greater reduction) for at least 1 week or there must be documentation in the medical chart that decreased immunosuppression would be associated with an unacceptable risk of rejection
• Patients must have a performance status corresponding to Eastern Cooperative Oncology Group (ECOG) scores of 0 or 1
• Use Karnofsky for patients > 16 years of age and Lansky for patients =< 16 years of age
• Patients must have a life expectancy of >= 8 weeks
• Patients must have fully recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to entering this study
• Myelosuppressive chemotherapy: must not have received within 2 weeks of entry onto this study
• COHORT A and B: Patient must not have received therapy with anti-CD20 monoclonal antibodies within 90 days of entry onto this study
• COHORT C: Patient must have received rituximab at 375 mg/m^2 weekly for at least 3 doses within the last 90 days prior to study enrollment
• Must not have received any prior radiation to any sites of measurable disease
• Must not have received any prior stem cell transplant
• Must not have received investigational therapy within 30 days of entry onto this study
• Must not have received prior EBV or LMP-specific T cells within 90 days of entry onto this study
• Must not have received alemtuzumab or other anti-T-cell antibody therapy within 28 days of entry onto this study
• COHORT C: HLA typing is available and will be submitted at the time of enrollment.
• Burkitt morphology
• Central nervous system (CNS) involvement; CNS status must be confirmed by lumbar puncture
• Note: lumbar puncture can be performed at the time of diagnosis and does not need to be repeated unless there is a change in neurological status or it was performed more than 14 days prior to study entry
• Bone marrow involvement (> 25%)
• Note: bone marrow aspiration/biopsy can be performed at the time of diagnosis and does not need to be repeated unless there is a change in peripheral blood counts or it was performed more than 14 days prior to study entry
• Fulminant PTLD defined as: fever > 38 degrees Celsius (C), hypotension, and evidence of multi-organ involvement/failure including two or more of the following:
• Bone marrow (including pancytopenia without any detectable B-cell proliferation)
• Liver (coagulopathy, transaminitis and/or hyperbilirubinemia)
• Lungs (interstitial pneumonitis with or without pleural effusions)
• Gastrointestinal hemorrhage
• Any documented donor-derived PTLD
• Hepatitis B or C serologies consistent with past or current infections because of the risk of reactivation with rituximab
• Severe and/or symptomatic refractory concurrent infection other than EBV
• Pregnant females are ineligible since there is no available information regarding human fetal or teratogenic toxicities
• Lactating females are not eligible unless they have agreed not to breastfeed their infants
• Female patients of childbearing potential are not eligible unless a negative pregnancy test result has been obtained
• Sexually active patients of reproductive potential are not eligible unless they have agreed to use an effective contraceptive method for the duration of their study participation and for 12 months following completion of study therapy.
• All patients and/or their parents or legal guardians must sign a written informed consent
• All institutional, Food and Drug Administration (FDA), and National Cancer Institute (NCI) requirements for human studies must be met

• All participants 12 to <18 years old must have documented positive CMV serostatus (CMV IgG seropositive) for the recipient (R+). Participants from birth to <12 years old must have documented positive CMV serostatus (CMV IgG seropositive) for the recipient (R+) and/or the donor (D+) and the time of screening.
• Is the recipient of a first allogeneic HSCT (bone marrow, peripheral blood stem cell, or cord blood transplant).
• Has undetectable CMV DNA from a plasma or whole blood sample collected within 5 days prior to enrollment.
• Is within 28 days post-HSCT at the time of enrollment.
• Females are not pregnant, not breastfeeding,and is not a woman of childbearing potential (WOCBP); or is a WOCBP who agrees to follow the contraceptive guidance during the treatment period and for at least 28 days after the last dose of study intervention.
• Participants from 2 to <18 years of age must not be on concomitant Cyclosporin A (CsA), and must be able to take LET tablets or the oral granules (either by mouth or via G tube/NG tube), provided the participant does not have a condition that may interfere with the absorption of oral medication (e.g. vomiting, diarrhea, or a malabsorptive condition) from the day of enrollment until the intensive PK sampling is completed in these participants
• Has received a previous allogeneic HSCT (Note: receipt of a previous autologous HSCT is acceptable).
• Has a history of CMV end-organ disease within 6 months prior to enrollment.
• Has evidence of CMV viremia at any time from either signing of the ICF or the HSCT procedure, whichever is earlier, until the time of enrollment.
• Has suspected or known hypersensitivity to active or inactive ingredients of LET formulations.
• Has severe hepatic insufficiency within 5 days prior to enrollment.
• Is on hemodialysis or has end-stage renal impairment.
• Has both moderate hepatic insufficiency and moderate-to-severe renal insufficiency.
• Has an uncontrolled infection on the day of enrollment.
• Requires mechanical ventilation or is hemodynamically unstable at the time of enrollment.
• Has a documented positive result for a human immunodeficiency virus antibody (HIVAb) test at any time prior to enrollment, or for hepatitis C virus antibody (HCV-Ab) with detectable HCV RNA, or hepatitis B surface antigen (HBsAg) within 90 days prior to enrollment.
• Has active solid tumor malignancies with the exception of localized basal cell or squamous cell skin cancer or the condition under treatment (e.g. lymphomas).
• Has a preexisting cardiac condition a) for which the patient is currently being treated or b) which required hospitalization within the last 6 months or c) that may be expected to recur during the course of the trial.
• Has received within 7 days prior to screening any of the following: ganciclovir; valganciclovir; foscarnet; acyclovir; valacyclovir; famciclovir.
• Has received within 30 days prior to screening of any of the following: cidofovir; CMV immunoglobulin; any investigational CMV antiviral agent/biologic therapy; Rifampin and other strong inducers (such as phenytoin, carbamazepine, St John's wort (Hypericum perforatum), rifabutin and phenobarbital) and moderate inducers such as nafcillin, thioridazine, modafinil and bosentan.
• Has received LET at any time prior to enrollment in this study.
• Is currently participating or has participated in a study with an unapproved investigational compound or device within 28 days, or 5X half-life of the investigational compound (excluding monoclonal antibodies), whichever is longer, of initial dosing in this study.
• Has previously participated in this study or any other study involving LET.
• Has previously participated or is currently participating in any study involving administration of a CMV vaccine or another CMV investigational agent, or is planning to participate in a study of a CMV vaccine or another CMV investigational agent during the course of this study.
• Is pregnant or expecting to conceive, is breastfeeding, or plans to breastfeed from the time of consent through 28 days after the last dose of study intervention.
• Is expecting to donate eggs starting from the time of consent through 28 days after the last dose of study intervention.
• Has clinically relevant drug or alcohol abuse within 12 months of screening that may interfere with participant treatment, assessment, or compliance with the protocol, as assessed by the investigator.

Key Inclusion Criteria (Parts A & B):
• A documented diagnosis of EoE by endoscopic biopsy
• Baseline endoscopic biopsies with a demonstration on central reading of intraepithelial eosinophilic infiltration
• History (by patient report) of an average of at least 2 episodes of dysphagia (with intake of solids) per week in the 4 weeks prior to screening Key Exclusion Criteria (Parts A & B):
• Body weight ≤40 kg
• Prior participation in a dupilumab clinical trial, or past or current treatment with dupilumab
• Initiation or change of a food-elimination diet regimen or re-introduction of a previously eliminated food group in the 6 weeks prior to screening.
• Other causes of esophageal eosinophilia or the following conditions: hypereosinophilic syndrome and eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)
• Active Helicobacter pylori infection
• History of achalasia, Crohn's disease, ulcerative colitis, celiac disease, and prior esophageal surgery
• Any esophageal stricture unable to be passed with a standard, diagnostic, 9 to10 mm upper endoscope or any critical esophageal stricture that requires dilation at screening
• History of bleeding disorders or esophageal varices
• Pregnant or breastfeeding women, or women planning to become pregnant or breastfeed during the study Key Exclusion Criteria (Part C):
• Participants who, during Part A or Part B, developed a serious adverse event (SAE) and/or adverse event (AE) deemed related to study drug, which in the opinion of the investigator could indicate that continued treatment with study drug may present an unreasonable risk for the participant
• Participants who became pregnant during Part A or Part B
• Participants who are prematurely discontinued from study drug due to an AE (patients who are prematurely discontinued from study drug due to lack of efficacy are eligible to enter Part C)
• Patients who did not undergo endoscopy with biopsies prior to receiving rescue treatment Note: Other inclusion/ exclusion criteria apply

• Patients who have had a high-risk Allogeneic Hematopoietic Transplant within 15 to 42 days of first dose in study
• Either no evidence of viral infection or viremia, or asymptomatic, viral infection with 3 or fewer viruses of interest at time of screening
• At least 1 identified, suitably matched Viralym-M cell line for infusion is available
• Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol.
• Contraceptive use by men and women consistent with local regulations regarding the methods of contraception for those participating in clinical studies.
• Not pregnant or breastfeeding
• Has a history of AdV, BKV, CMV, HHV-6, and/or JCV end-organ disease within 6 months prior to treatment assignment
• Evidence of active Grade >2 graft versus host disease (GVHD)
• Presence of non-minor uncontrolled or progressive bacterial or fungal infections (ie, evidence of bacteremia, fungemia, disseminated)
• Ongoing therapy with high-dose systemic corticosteroids
• Pregnant or lactating or planning to become pregnant
• Weight <30 kg

Patients who meet all of the following inclusion criteria will be eligible to participate in the study: 1. Male or female patients 18 years of age or older. 2. Patients must be eligible to undergo kidney transplantation from a living donor as per institutional standards. 3. For Groups 1 and 2 only: Patients must be CMV immunoglobulin G (IgG) seronegative (-) and receiving kidney for transplantation from donors who are CMV IgG seropositive (+). 4. For Group 3 only: Patients must be CMV immunoglobulin G (IgG) seropositive (+) and receiving kidney for transplantation from donors who are either CMV IgG seronegative (-) or seropositive (+). 5. Patients who would comply with the requirements of this protocol (e.g., return for follow up visits), as judged by the investigator. Patients who meet any of the following criteria will be excluded from the study: 1. Patients planning to undergo multi-organ transplantation. 2. Patients participating in another interventional clinical study. 3. Previous vaccination with an investigational CMV vaccine. 4. Any confirmed or suspected immunodeficiency disorder (based on medical history and physical examination) that could interfere with the immune response or that presents a risk for the patient to receive a vaccine candidate in development. 5. Treatment with any chronic immunosuppressive medication or other immuno modifying drugs within 6 months prior to study entry. However, inhaled and topical steroids and low-dose oral corticosteroids (<10 milligrams a day of prednisone or equivalent) are allowed. 6. Prior history of CMV disease or CMV infection requiring anti-viral therapy 7. Patients with a rash, dermatological condition, or tattoo in the area of the injection site(s) that could interfere with administration site reaction rating. (Note: The injection site(s) can be the non-dominant arm [most preferred injection site], dominant arm, or either thigh [least preferred injection site], as judged by the investigator). 8. It is anticipated that the patient will be unavailable to complete the study follow-up.

• Men and non-pregnant women 18-80 years old who were previously hospitalized with confirmed COVID-19
• Were alive at the time of discharge from COVID-19 hospitalization
• Had measured hs-cTnT levels during hospitalization
• Prior cardiovascular disease (before COVID-19 infection), defined as self-reported history or electronic medical record diagnosis of cardiac arrest, myocardial infarction, coronary revascularization, heart failure, or stroke prior to COVID-19 hospitalization
• Urgent-coronary revascularization or type I myocardial infarction within the preceding 30 days
• Cardiac transplantation
• Body weight >250 lbs
• Moderate to severe chronic renal dysfunction defined by an eGFR ≤30 mL/min/1.73 m2
• Inability to safely undergo a CMR
• Unwilling or unable to provide informed consent

• SARS-CoV-2 infection documented by PCR or other nucleic acid test (NAT) within 3 days prior to randomization OR documented by NAT more than 3 days prior to randomization AND progressive disease suggestive of ongoing SARS-CoV-2 infection
• Symptomatic COVID-19 disease
• Duration of symptoms attributable to COVID-19 ≤ 12 days
• Requiring inpatient hospital medical care for clinical manifestations of COVID-19 (admission for public health or quarantine only is not included)
• Willingness to abstain from participation in other COVID-19 treatment trials until after study Day 7
• Provision of informed consent by participant or legally authorized representative
• Prior receipt of SARS-CoV-2 hIVIG or convalescent plasma from a person who recovered from COVID-19 at any time
• Prior receipt of standard IVIG (not hyperimmune to SARS-CoV-2) within 45 days
• Current or predicted imminent (within 24 hours) requirement for any of the following: 1. Invasive ventilation 2. Non-invasive ventilation 3. Extracorporeal membrane oxygenation 4. Mechanical circulatory support 5. Continuous vasopressor therapy
• History of allergy to IVIG or plasma products
• History of selective IgA deficiency with documented presence of anti-IgA antibodies
• Any medical conditions for which receipt of the required volume of intravenous fluid may be dangerous to the patient (includes New York Association Class III or IV stage heart failure)
• Any of the following thrombotic or procoagulant disorders: 1. Acute coronary syndromes, cerebrovascular syndromes and pulmonary or deep venous thrombosis within 28 days of randomization 2. History of prothrombin gene mutation 20210, homozygous Factor V Leiden mutations, antithrombin III deficiency, protein C deficiency, protein S deficiency or antiphospholipid syndrome
• Any condition for which, in the opinion of the investigator, participation would not be in the best interest of the subject or that could prevent, limit, or confound the protocol-specified assessments

• COVID-19 PCR positive (within 7 days)
• COVID-19 PCR pending
• COVID-19 high clinical suspicion
• Patient without Prior Research Authorization (applicable to Mayo Clinic sites)
• Non COVID-19 related admissions
• Repeated Admission to ICUs/Hospital

• INCLUSION CRITERIA:
• Written informed consent
• At least 18 years of age
• HBsAg-positive and either
• Pregnant
• Anti-HDV positive
• Diagnosed with acute HBV infection or experiencing a hepatitis flare
• Immune tolerant or immune active phenotype
• Potentially eligible for the Immune Regulation and Costimulation in Natural History of Chronic Hepatitis B ancillary study. EXCLUSION CRITERIA:
• History of hepatic decompensation
• Hepatocellular carcinoma (HCC)
• History of solid organ transplantation or bone marrow transplantation
• Current hepatitis B antiviral treatment (except pregnant women and patients who are anti-HDV positive)
• Chronic immunosuppression therapy
• Known HIV co-infection (patients with HDV or HCV co-infection are not excluded)
• Medical or social condition which, in the opinion of the investigator, would make the patient unsuitable for the study or interfere with or prevent follow-up per protocol
• Unable or unwilling to return for follow-up visits

• Enrolled in & completed the baseline evaluation in NCT01263600 OR completed necessary components of NCT01263600 baseline evaluation by the end of the baseline visit.
• 3 to <18 years at time of randomization (day 0).
• Documented chronic HBV infection as evidenced by detection of HBsAg in serum for ≥ 24 weeks prior to baseline OR positive HBsAg and negative anti-HBc IgM within 24 weeks of baseline visit.
• Presence of HBeAg in serum at the last screening visit within 6 weeks of baseline visit.
• Serum HBV DNA level >10^7 IU/mL on at least 2 occasions at least 12 weeks apart during the 52 weeks before baseline visit. The HBV DNA levels must be within 6 weeks of baseline visit.
• ALT ≤60 U/l in males or ≤40 U/l in females, measured on at least 2 occasions, at screening (within 6 weeks prior to baseline visit) & at least 12 weeks prior to the screening visit & within the 52 weeks prior to baseline visit.
• Compensated liver disease, with normal total bilirubin (except if Gilbert's syndrome), direct bilirubin ≤0.5 mg/dL, INR ≤1.5, and serum albumin ≥3.5 g/dL.
• Creatinine clearance 90 ml/min.
• Absence of hepatocellular carcinoma on liver ultrasound in the past 48 weeks. Exclusion criteria:
• Presence of infection with HCV-RNA or anti-HCV, anti-HDV, or HIV at screening.
• Presence of another cause of liver disease or HCC (serum alpha-fetoprotein >50ng /ml).
• Evidence of decompensated liver disease (Childs B-C).
• History or other evidence of a medical condition associated with chronic liver disease (e.g., hemochromatosis, autoimmune hepatitis, alcoholic liver disease, toxin exposures).
• Females who are pregnant or breastfeeding.
• Adolescent females unwilling or unable to use an acceptable method of contraception if sexually active during the treatment period.
• Children currently breastfeeding while their mother is taking lamivudine, or those who were exposed to lamivudine for ≥24 weeks via maternal lamivudine treatment during pregnancy and/or while breastfeeding.
• Previous liver or other organ transplantation including engrafted bone marrow transplant.
• Hematological abnormalities during the screening period that contraindicate full dosing with study drugs, e.g absolute neutrophil count < 1.5 x 10^9 cells/L or platelet count < 120 x 10^9 cells/L.
• Known allergy to study drugs; peginterferon alfa-2a or entecavir.
• Treatment with systemic acyclovir or famciclovir within the previous 6 months.
• Need for ongoing use of any antivirals with activity against HBV during the course of the study or history of receiving treatment for HBV.
• Any use of illegal drugs OR use of alcoholic beverages which in the opinion of a study physician is sufficient to prevent adequate compliance with study procedures or increase the risk of pancreatitis or hepatotoxicity.
• History of immunologically mediated disease (e.g. inflammatory bowel disease, idiopathic thrombocytopenic purpura, lupus erythematosus, autoimmune haemolytic anemia, scleroderma, severe psoriasis, rheumatoid arthritis).
• History or other evidence of bleeding from esophageal varices or consistent with decompensated liver disease.
• History or other evidence of chronic pulmonary disease associated with functional limitation.
• History of significant cardiovascular diseases.
• History of a severe seizure disorder or current anticonvulsant use.
• History or other evidence of severe retinopathy.
• History of thyroid disease poorly controlled on prescribed medications. Participants with elevated thyroid stimulating hormone concentrations with elevation of antibodies to thyroid peroxidase and any clinical manifestations of thyroid disease are excluded.
• Concomitant use or use during ≤ 6 months prior to the first dose of study drug of anti-neoplastic, immunosuppressive, nephrotoxic or hepatotoxic medication, methadone, theophylline or medications that may affect renal excretion or hepatic metabolism are not permitted.
• Concomitant use of complementary or alternative medications purported to have antiviral activity.
• A participant may not be co-enrolled in another clinical trial where an investigational drug is administered.
• Any other condition or situation that in the opinion of a study physician would make the participant unsuitable for enrollment or could interfere with the participant participating in and completing the study.

• Infants born at ≤1,000 g birth weight
• Infant is ≤8 0/7 weeks of age at the time of eligibility assessment
• Pediatric surgeon decision to perform surgery for suspected NEC or IP
• Subject is at a center able to perform both laparotomy and drainage
• Major anomaly that influences likelihood of developing primary outcome or affects surgical treatment considerations
• Congenital infection
• Prior laparotomy or peritoneal drain placement
• Prior NEC or IP
• Infant for whom full support is not being provided
• Follow-up unlikely

• Signed informed consent.
• Positive test for COVID-19 and progressive disease suggestive of ongoing COVID-19 infection.
• Symptoms of COVID-19 for ≤ 12 days.
• Require admission to hospital for acute medical care (not for purely public health or quarantine purposes).
• Patients who have received plasma from a person who recovered from COVID-19 or who have received neutralizing monoclonal antibodies at any time prior to hospitalization.
• Patients not willing to abstain from participation in other COVID-19 treatment trials until after Day 5 of the study. Co-enrollment in certain trials that compare recommended Standard of Care treatments may be allowed, based on the opinion of the study leadership team.
• Any condition which, in the opinion of the responsible investigator, participation would not be in the best interest of the participant or that could prevent, limit, or confound the protocol-specified assessments.
• Patients considered unable to participate in study procedures.
• Women of child-bearing potential who are not already pregnant at study entry and who are unwilling to acknowledge strong advice to abstain from sexual intercourse with men or practice appropriate contraception through 18 months of the study.
• Men who are unwilling to acknowledge the strong advice to abstain from sexual intercourse with women of child-bearing potential or to use barrier contraception through 18 months of the study.
• Presence at study enrollment of any of the following: 1. stroke 2. meningitis 3. encephalitis 4. myelitis 5. myocardial ischemia 6. myocarditis 7. pericarditis 8. symptomatic congestive heart failure 9. arterial or deep venous thrombosis or pulmonary embolism
• Current or imminent requirement for any of the following: 1. invasive mechanical ventilation 2. ECMO (extracorporeal membrane oxygenation) 3. Mechanical circulatory support 4. vasopressor therapy 5. commencement of renal replacement therapy at this admission (i.e. not patients on chronic renal replacement therapy).

1. Males and females, at least 40 years of age, capable and willing to provide informed consent; 2. Patient must have received a diagnosis of COVID-19 infection within the last 24 hours; 3. Outpatient setting (not currently hospitalized or under immediate consideration for hospitalization); 4. Patient must possess at least one of the following high-risk criteria: 70 years or more of age, obesity (BMI ≥ 30 kg/m2), diabetes mellitus, uncontrolled hypertension (systolic blood pressure ≥150 mm Hg), known respiratory disease (including asthma or chronic obstructive pulmonary disease), known heart failure, known coronary disease, fever of ≥38.4°C within the last 48 hours, dyspnea at the time of presentation, bicytopenia, pancytopenia, or the combination of high neutrophil count and low lymphocyte count; 5. Female patient is either not of childbearing potential, defined as postmenopausal for at least 1 year or surgically sterile, or is of childbearing potential and practicing at least one method of contraception and preferably two complementary forms of contraception including a barrier method (e.g. male or female condoms, spermicides, sponges, foams, jellies, diaphragm, intrauterine device (IUD)) throughout the study and for 30 days after study completion; 6. Patient must be able and willing to comply with the requirements of this study protocol. 1. Patient currently hospitalized or under immediate consideration for hospitalization; 2. Patient currently in shock or with hemodynamic instability; 3. Patient with inflammatory bowel disease (Crohn's disease or ulcerative colitis), chronic diarrhea or malabsorption; 4. Patient with pre-existent progressive neuromuscular disease; 5. Estimated Glomerular filtration rate (eGFR), using the MDRD equation for all subjects being considered for enrollment, with a cut-off of < 30 mL/m in/1.73m2; 6. Patient with a history of cirrhosis, chronic active hepatitis or severe hepatic disease; 7. Female patient who is pregnant, or breast-feeding or is considering becoming pregnant during the study or for 6 months after the last dose of study medication; 8. Patient currently taking colchicine for other indications (mainly chronic indications represented by Familial Mediterranean Fever or gout); 9. Patient with a history of an allergic reaction or significant sensitivity to colchicine; 10. Patient undergoing chemotherapy for cancer; 11. Patient is considered by the investigator, for any reason, to be an unsuitable candidate for the study.

1. Diagnosis of Multiple Sclerosis , ADEM, anti-MOG antibody associated CNS demyelination 2. Age 12 to 18 inclusive at time of enrollment 3. Ability of parent or legal guardian to provide informed consent if participant is under 18. 4. Ability of patients age 12 and older to give assent 5. Completion of the signed HIPPA authorization form by a parent or legal guardian or by participants (18 years of age). 1. Known history of traumatic brain injury that required medical care 2. Non-English speaking (based on standardized neuropsychological testing and questionnaires) 3. Claustrophobic, pregnant, the presence of metallic braces, implants or medical devices that are unsafe at 3T or 7T and/or interfere with the MRI/MRS signals

• Participant meets the standard criteria for liver transplant at the local center.
• Participants being listed for a simultaneous liver kidney (SLK) are eligible if participants meet the standard criteria for both organs.
• Participant is able to understand and provide informed consent.
• Participant meets with an independent advocate per the HIV Organ Policy Equity (HOPE) Act Safeguards and Research Criteria.
• Documented HIV infection (by any licensed assay or documented history of detectable HIV-1 RNA).*
• Participant is ≥ 18 years old.
• Opportunistic complications: prior history of certain opportunistic infections is not an exclusion if the participant has received appropriate therapy and has no evidence of active disease. Medical record documentation should be provided whenever possible.
• CD4+ T-cell count: ≥ 100/µL within 16 weeks prior to transplant if no history of AIDS-defining infection; or ≥ 200 μL if history of opportunistic infection is present.
• HIV-1 RNA is below 50 RNA/mL.* Viral blips between 50-400 copies will be allowed as long as there are not consecutive measurements > 200 copies/mL. *Organ recipients who are unable to tolerate anti-retroviral therapy (ART) due to organ. failure or recently started ART may be eligible despite a detectable viral load if safe and effective ART to be used by the recipient after transplantation is described.
• Participant must have or be willing to start seeing a primary medical care provider with expertise in HIV management.
• Participant is willing to comply with all medications related to participant's transplant and HIV management.
• For participants with a history of aspergillus colonization or disease, no current clinical evidence of active disease.
• Agreement to use contraception.
• Participant is not suffering from significant wasting (e.g. body mass index < 21) thought to be related to HIV disease.
• Participant has a history of progressive multifocal leukoencephalopathy (PML), or primary central nervous system (CNS) lymphoma.*
• Participant is pregnant or breastfeeding. (Note: Participants who become pregnant post-transplant will continue to be followed in the study and will be managed per local site practice. Women that become pregnant should not breastfeed.)
• Past or current medical problems or findings from medical history, physical examination or laboratory testing that are not listed above, which, in the opinion of the investigator, may pose additional risks from participation in the study, may interfere with the participant's ability to comply with study requirements or that may impact the quality or interpretation of the data obtained from the study.

• Age greater than or equal to 1 month and less than or equal to 12 months at the time of randomization; AND
• Positive congenital CMV by urine culture or polymerase chain reaction test(PCR), OR saliva culture or PCR followed by confirmatory urine PCR by 21 days of age, OR urine culture or PCR after 21 days of age followed by newborn dry blood spot PCR; AND
• Confirmed sensorineural hearing loss (SNHL) by auditory brainstem response (ABR) testing. For ABR assessments, hearing loss is defined as levels greater than 25 dB normal hearing levels (NHL) at 1, 2, or 4 kHz in one or both ears.
• Imminent demise; OR
• Known hypersensitivity reaction to valganciclovir, ganciclovir, or any components of the investigational product formulation; OR
• ALT (Alanine Aminotransferase) five times baseline U/L, hepatomegaly, or significant gastrointestinal disorders (e.g., eosinophilic esophagitis, ulcerative colitis); OR
• Absolute neutrophil count (ANC) less than 500 cells/mm^3, Hemoglobin less than 8 g/dL, or platelets less than 50,000/mm^3, splenomegaly, or significant hematologic disorders (e.g., hemophilia, leukemia, sickle cell anemia); OR
• Creatinine clearance less than 60 mL/min/1.73m^2 or significant renal disorders (e.g., nephrotic syndrome); OR
• Receiving other antiviral medications or immune globulin therapy; OR
• Receiving other investigational drugs; OR
• Breast feeding from a mother receiving antiviral or immunosuppressive medication; OR
• Known HIV positive mother (risk of immunosuppression); OR
• Subject is currently using list of prohibited medication specified by the package insert; OR
• Other known cause contributing to SNHL (e.g., meningitis, aminoglycoside ototoxicity); OR
• Bilateral profound SNHL or auditory neuropathy spectrum disorder; OR
• Existing conductive hearing loss or mixed permanent hearing loss is present; OR
• Evidence of intracranial calcification; OR
• Evidence of hydrocephalus; OR
• Microcephaly; OR
• Presence of petechiae; OR
• Intrauterine growth retardation; OR
• Chorioretinitis, optic atrophy or pale optic nerves; OR
• Parent or guardian unable to speak English or Spanish; OR
• Subject exposed to a language other than English or Spanish a majority of the time; OR
• Subject unable to complete hearing assessments or parent/guardian unable to complete communication questionnaires; OR
• < 32 weeks gestational age at birth; OR
• Weight at the time of birth < 1800 g.

Key
• Has SARS-CoV-2-positive antigen or molecular diagnostic test (by validated SARS-CoV-2 antigen, RT-PCR, or other molecular diagnostic assay, using an appropriate sample such as NP, nasal, oropharyngeal [OP], or saliva) ≤72 hours prior to randomization. A historical record of positive result from test conducted ≤72 hours prior to randomization is acceptable
• Meets 1 of the following 2 criteria: 1. Symptomatic Cohort (All Phases): Has symptoms consistent with COVID-19, as determined by the investigator, with onset ≤7 days before randomization or 2. Asymptomatic Cohort (Phase 2): Meets all of the following:
• Has had no symptoms consistent with COVID-19 (as determined by the investigator) occurring at any time <2 months prior to randomization
• Has had no positive SARS-CoV-2 test results from a sample collected >7 days prior to randomization
• Has had no known contact (of any duration) with an individual who has confirmed COVID-19 or confirmed positive SARS-COV-2 test result >14 days prior to randomization.
• Has experienced COVID-19 symptoms for <7 days
• Has symptoms consistent with COVID-19, as determined by investigator, with onset ≤7 days before randomization Key
• Has been admitted to a hospital prior to randomization, or is hospitalized (inpatient) at randomization, due to COVID-19
• Has participated, or is participating, in a clinical research study evaluating COVID-19 convalescent plasma, monoclonal antibodies (mAbs) against SARS-CoV-2, or intravenous immunoglobulin (IVIG) within 3 months or less than 5 half-lives of the investigational product (whichever is longer) prior to the screening visit
• Prior, current, or planned future use of any of the following treatments: COVID-19 convalescent plasma, mAbs against SARS-CoV-2, IVIG (any indication), systemic corticosteroids (any indication), or COVID-19 EUA approved treatments, where prior use is defined as the past 30 days or less than 5 half-lives of the investigational product (which is longer) from screening NOTE: Other Protocol defined Inclusion/Exclusion criteria apply

Key
• Aged < 18 years of age who meet one of the following weight criteria (where permitted according to local law and approved nationally and by relevant institutional review board (IRB) or independent ethics committee (IEC)).
• a) Cohort 1: ≥ 12 years to < 18 years of age and weight at screening ≥ 40 kg
• b) Cohorts 2-4: ≥ 28 days to < 18 years of age and weight at screening ≥ 3 kg and < 40 kg
• c) Cohort 5: ≥ 14 days to < 28 days of age, gestational age > 37 weeks and weight at screening ≥ 2.5 kg
• d) Cohort 6: 0 days to < 14 days of age, gestational age > 37 weeks and birth weight of ≥ 2.5 kg
• e) Cohort 7: 0 days to < 56 days of age, gestational age ≤ 37 weeks and birth weight of ≥ 1.5 kg
• f) Cohort 8: < 12 years of age and weight at screening ≥ 40 kg
• Severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection confirmed by polymerase chain reaction (PCR)
• Hospitalized and requiring medical care for coronavirus disease 2019 (COVID-19) Key
• Concurrent treatment with other agents with actual or possible direct antiviral activity against SARS-CoV-2 < 24 hours prior to study drug dosing
• Alanine Aminotransferase (ALT) or aspartate aminotransferase (AST) > 5 X upper limit of normal (ULN)
• Estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73m^2 using Schwartz formula for individuals ≥ 1 year of age
• Creatinine above protocol specified thresholds for < 1 year of age
• Positive pregnancy test at Screening only for female of child bearing potential. Note: If female participants who become pregnant during the study or are discovered to be pregnant after receiving at least one dose may continue study drug, after discussion with the investigator
• On renal replacement therapies (intermittent hemodialysis (iHD), peritoneal dialysis (PD), continuous renal replacement therapy (CRRT)) Note: Other protocol defined Inclusion/Exclusion criteria may apply

• One or more symptoms of COVID-19 illness and laboratory-confirmed SARS-CoV-2 infection
• Has at least one study defined risk factor for severe COVID-19 illness
• Clinical team deems stable for outpatient management without supplemental oxygen
• CP available at the site at the time of enrollment
• Duration of symptoms ≤ 7 days at ED presentation
• Informed consent from subject
• Age less than 18 years
• Prisoner or ward of the state
• Presumed unable to complete follow-up assessments
• Prior adverse reaction(s) from blood product transfusion
• Receipt of any blood product within the past 120 days
• Treating clinical team unwilling to administer 300 ml fluid
• Enrollment in another interventional trial for COVID-19 illness

• At least 18 years old
• Able to read and speak English
• Able to read and understand the Informed Consent Form
• Willing to wear Verily Patch in the axillary region
• Willing to comply with repeated self-measurement of oral and axillary temperatures and willing to record temperature readings
• Have a working smartphone device and willing to use it for study activities
• Willing to install study apps on their personal smartphone
• Willing to comply with all study-related procedures
• Pregnant or breastfeeding during study participation
• Have known allergies to medical grade adhesives
• Have known cutaneous hypersensitivity
• Have infection in both axilla
• Have open injury or rash where the study device will be worn
• Have a cardiac pacemaker or other implanted electronic medical device(s)
• Have any additional condition or situation that, in the opinion of the investigator, makes the subject inappropriate for participation in the study

• Previously participated in a HCV treatment protocol that included grazoprevir in the treatment regimen
• Must enroll in the present study within three months of the last study visit of their previous protocol in which they received a grazoprevir-containing regimen
• For Amendment 03: Adult participants must have received a grazoprevir-containing regimen in a prior trial and have been identified as having failed therapy in that study
• For Amendment 04: Pediatric participants must have received at least 1 dose of a grazoprevir-containing regimen and experienced virologic failure with 1 or more associated treatment-emergent RASs at Follow-up Week 12 in MK-5172-079 (NCT03379506)
• Has received HCV therapy after completion of the protocol-defined grazoprevir treatment trial regimen and before or after entry into this follow-up study
• For Amendment 03: Has failed therapy due to re-infection, defined as an HCV RNA sample with a different genotype than the baseline genotype in the prior treatment study, or an HCV RNA sample determined to be reinfection by phylogenetic analysis with comparison to the baseline sequence in the prior treatment study
• For Amendment 03: Has failed therapy and received retreatment with HCV therapy, except in the case where they were re-treated in a Merck-sponsored protocol