EPIC-Peds: A Study to Learn About the Study Medicine Called PF-07321332 (Nirmatrelvir)/Ritonavir in Patients Under 18 Years of Age With COVID-19 That Are Not Hospitalized But Are at Risk for Severe Disease

Inclusion criteria:

• Male and female, age 0 to < 18 years, able to swallow for some participants

• Confirmed SARS-CoV-2 infection within 72 hours prior to enrollment

• Initial onset of COVID-19 signs/symptoms within 5 days prior to the day ofenrollment and at least 1 of the specified COVID-19 signs/symptoms present atenrollment

• Has at least 1 characteristic or underlying medical condition associated with anincreased risk of developing severe illness from COVID-19

Exclusion Criteria:

• History of or need for hospitalization for the medical treatment of COVID-19

• Total bilirubin >=2X upper limit of normal (ULN) (except for Gilbert's syndrome)

• Receiving dialysis or have known moderate to severe renal impairment

• Suspected or confirmed concurrent active systemic infection other than COVID-19

• History of hypersensitivity or other contraindication to any of the components ofthe study intervention

• Current or expected use of any medications or substances that are highly dependenton CYP3A4 for clearance or strong inducers of cytochrome P450 (CYP)3A4

• Has received or is expected to receive antibody treatment, antiviral treatment orconvalescent COVID-19 plasma

• Participating in another interventional clinical study with an investigationalcompound or device, including those for COVID-19 through the study follow up

• Females who are pregnant or breastfeeding