1. The participant is a household contact of an index case. The index case is a person with documented COVID-19 (laboratory-confirmed SARS-CoV-2 infection with symptoms case) and must have: a) A first positive SARS-CoV-2 test result from a sample collected within 72 hours prior to randomization of the participant(s), AND b) At least 1 of the following symptoms attributable to COVID-19: fever ≥38.0ºC, chills, cough, sore throat, shortness of breath or difficulty breathing with exertion, fatigue, nasal congestion, runny nose, headache, muscle or body aches, nausea, vomiting, diarrhea, loss of taste, or loss of smell, with symptom onset no earlier than 5 days prior to randomization of the participant(s). 2. The participant does not have confirmed or suspected COVID-19. 3. The participant is willing and able to take oral medication. 4. The participant is male or female ≥18 years of age, at the time of providing documented informed consent. 5. Male participants are eligible to participate if they agree to the following during the intervention period and for at least 4 days after the last dose of study intervention: Be abstinent from heterosexual intercourse as their preferred and usual lifestyle (abstinent on a long-term and persistent basis) and agree to remain abstinent OR Must agree to use contraception unless confirmed to be azoospermic (vasectomized or secondary to medical cause) as detailed below: - Agree to use a male condom plus partner use of an additional contraceptive method when having penile-vaginal intercourse with a WOCBP who is not currently pregnant. - Contraceptive use by men should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies. 6. A female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies: Is not a WOCBP OR Is a WOCBP and using a contraceptive method that is highly effective (with a failure rate of <1% per year), with low user dependency, or be abstinent from heterosexual intercourse as their preferred and usual lifestyle (abstinent on a long-term and persistent basis), during the intervention period and for at least 4 days after the last dose of study intervention. The investigator should evaluate the potential for contraceptive method failure (ie, noncompliance, recently initiated) in relationship to the first dose of study intervention. - A WOCBP must have a negative highly sensitive pregnancy test (urine or serum as required by local regulations) within 24 hours before the first dose of study intervention. - The investigator is responsible for review of medical history, menstrual history, and recent sexual activity to decrease the risk for inclusion of a woman with an early undetected pregnancy. - Contraceptive use by women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies. - If contraceptives are interrupted in case of standard of care management of COVID-19 and resumed at a later time point, then abstinence must be practiced for the defined period of back-up contraception per the contraceptive product labeling. After this period, contraceptive use must adhere to protocol. 7. The participant’s index case (or legally acceptable representative of the index case) has provided documented informed consent/assent for the collection of COVID-19 documentation requirements. 8. The participant (or legally acceptable representative) has provided documented informed consent to participate in the study. The participant may also provide consent for participation in FBR but may participate in the study without participating in FBR.

1. The participant is a household contact of an index case. The index case is a person with documented COVID-19 (laboratory-confirmed SARS-CoV-2 infection with symptoms case) and must have: a) A first positive SARS-CoV-2 test result from a sample collected within 72 hours prior to randomization of the participant(s), AND b) At least 1 of the following symptoms attributable to COVID-19: fever ≥38.0ºC, chills, cough, sore throat, shortness of breath or difficulty breathing with exertion, fatigue, nasal congestion, runny nose, headache, muscle or body aches, nausea, vomiting, diarrhea, loss of taste, or loss of smell, with symptom onset no earlier than 5 days prior to randomization of the participant(s). 2. The participant does not have confirmed or suspected COVID-19. 3. The participant is willing and able to take oral medication. 4. The participant is male or female ≥18 years of age, at the time of providing documented informed consent. 5. Male participants are eligible to participate if they agree to the following during the intervention period and for at least 4 days after the last dose of study intervention: Be abstinent from heterosexual intercourse as their preferred and usual lifestyle (abstinent on a long-term and persistent basis) and agree to remain abstinent OR Must agree to use contraception unless confirmed to be azoospermic (vasectomized or secondary to medical cause) as detailed below: - Agree to use a male condom plus partner use of an additional contraceptive method when having penile-vaginal intercourse with a WOCBP who is not currently pregnant. - Contraceptive use by men should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies. 6. A female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies: Is not a WOCBP OR Is a WOCBP and using a contraceptive method that is highly effective (with a failure rate of <1% per year), with low user dependency, or be abstinent from heterosexual intercourse as their preferred and usual lifestyle (abstinent on a long-term and persistent basis), during the intervention period and for at least 4 days after the last dose of study intervention. The investigator should evaluate the potential for contraceptive method failure (ie, noncompliance, recently initiated) in relationship to the first dose of study intervention. - A WOCBP must have a negative highly sensitive pregnancy test (urine or serum as required by local regulations) within 24 hours before the first dose of study intervention. - The investigator is responsible for review of medical history, menstrual history, and recent sexual activity to decrease the risk for inclusion of a woman with an early undetected pregnancy. - Contraceptive use by women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies. - If contraceptives are interrupted in case of standard of care management of COVID-19 and resumed at a later time point, then abstinence must be practiced for the defined period of back-up contraception per the contraceptive product labeling. After this period, contraceptive use must adhere to protocol. 7. The participant’s index case (or legally acceptable representative of the index case) has provided documented informed consent/assent for the collection of COVID-19 documentation requirements. 8. The participant (or legally acceptable representative) has provided documented informed consent to participate in the study. The participant may also provide consent for participation in FBR but may participate in the study without participating in FBR.