The purpose of this study is to understand how the loss of kidney function affects study medicine (PF-07923568) in the body. People with some level of loss of kidney function may process PF-07923568 differently from healthy people. PF-07923568 is developed as a possible treatment for respiratory syncytial virus (RSV) infection. RSV is a common virus that affects the lungs and usually causes mild, cold-like symptoms. RSV can cause severe lung infections in infants, elderly, and adults with other serious medical conditions.

This study is seeking participants who:

• Have less than 25% difference in kidney function between 2 screening visits.
• Meet the eGFR criteria for being assigned to groups. eGFR tells how well the kidney is filtering.
• Are not on hemodialysis. Hemodialysis is a type of treatment that helps the body remove extra fluid and waste products from the blood when the kidneys are not able to.

Participants will take the study medicine as capsules by mouth once at the study clinic. The participants will stay at the study clinic for about 5 days. During that time, the study team will monitor the participants. The study team will take some blood samples to test the level of PF-07923568. This will help us understand if some level of loss of kidney function will have an effect on the study medicine PF-07923568.

Inclusion Criteria:

1. Stable renal function defined as ≤25% difference between 2 measurements of absolute estimated glomerular filtration rate (eGFR) during screening.
2. Meet the eGFR criteria for cohort placement during the screening period.
3. Body mass index (BMI) of 16-40 kg/m2; and a total body weight >45 kg (99 lb.).
4. For Cohort 2 Normal Renal Function Group Only: At screening, meet the demographic-matching criteria, including body weight within ±15 kg and age within ±10 years, of the average of the pooled renal impairment cohort.

Exclusion Criteria:

1. Participants with acute renal disease.
2. Participants who are clinically nephrotic.
3. Participants requiring hemodialysis.
4. Renal allograft recipients.
5. Participants who have previously received a kidney, liver, or heart transplant.
6. Urinary incontinence without catheterization.
7. History of human immunodeficiency virus (HIV) infection, hepatitis B, or hepatitis C; positive testing for HIV, hepatitis B surface antigen (HBsAg), or hepatitis C antibody (HCVAb).
8. History of alcohol abuse or binge drinking and/or any other illicit drug use or dependence within 6 months of Screening.
9. Participation in studies of other investigational products (drug or vaccine) at any time during their participation in this study.

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.