The purpose of the study is to learn about the safety of PF-07817883 and how PF-07817883 is processed in the body of adult participants. These participants will have different degrees of loss of liver function. Participants with mild, moderate, severe or no loss of liver function will be enrolled in 4 groups.

This study is seeking participants who:

• are male or female of 18- 75 years of age
• either have different amounts of damage to liver function or for one of the groups, no damage
• willing to follow the requirements of the study including stay at clinic for 6 nights and 7 days

About, 6-8 participants will be enrolled in group 1 (participants without loss of liver function) and group 3 (participants with moderate loss of liver function). In group 4 (participants with severe loss of function), around 4 to 8 participants will be enrolled. Participants in group 2 (mild loss of function) will only be enrolled after review of the data from groups 3 and 4.

If participants consent to participate in the study, it may take up to 4 weeks to complete all the tests to confirm if they are eligible to participate in the study. If they seem to be eligible for the study, participants will be admitted to a clinic research unit (CRU) at least 12 hours before dosing. On Day 1, participants will receive a single dose of study medicine (Day 1). A series of blood samples will be collected before and after dosing. Participants will be discharged from the CRU on Day 6. A follow-up phone call (on CRU visit, if needed), will occur 28-35 days after dosing.

The whole study will last for a minimum of 5 weeks and a maximum of 10 weeks.

Inclusion Criteria:

• (HI Cohorts Only): Stable HI that meets criteria for Class A or B of the Child-Pugh classification;
• (all Cohorts): BMI of 17.5 to 38.0 kg/m2

Exclusion Criteria:

• Any condition possibly affecting drug absorption Additional Exclusion Criteria for HI Cohorts Only
• Limited predicted life expectancy
• Hepatic dysfunction secondary to acute ongoing hepatocellular process.
• Signs of clinically active Grade 2, 3 or 4 hepatic encephalopathy.
• Severe ascites and/or pleural effusion
• History of kidney, liver, or heart transplantation.
• Persistent severe, uncontrolled hypertension.

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.