The purpose of the Phase 3 study is to evaluate the safety, pharmacokinetics, and efficacy of nirmatrelvir/ritonavir for the treatment of nonhospitalized, symptomatic pediatric participants with coronavirus disease 2019 (COVID-19) who are at risk of progression to severe disease.

140 pediatric participants (up to 18 years old) will be recruited for this study.

Inclusion criteria:

• Male/female
• Able to swallow tablets
• Positive SARS-CoV-2 infection within 5 days prior to enrollment
• At least 1 characteristic or underlying medical condition that could increase the risk of developing severe COVID-19 illness