A Study to Learn About the Medicine (PF-07321332 or Nirmatrelvir/Ritonavir) in Healthy Lactating Women

Inclusion Criteria: * Healthy lactating females who are actively breast-feeding or expressing breast milk, at least 12 weeks post-partum and not currently pregnant between 18 and 55 years old * Body Mass Index (BMI): 17.5 kg/m2; and a total body weight \>50 kg (110 lb) * Infants of women enrolled in the study must be able to feed successfully from a bottle or other age-appropriate alternative feeding method prior to the start of the study and must be able to tolerate infant formula if the mother does not have a supply of stored breast milk sufficient to cover the duration of the study * Participants must be willing to temporarily discontinue breast feeding their infants for a total of 4.5 days (108 hours) * Participants must be willing to regularly pump breasts throughout the study and express milk according to a schedule designed to maintain lactation throughout the study period Exclusion Criteria: * Positive test result (RT-PCR) for SARS-CoV-2 infection at the time of screening or Day -1 * Evidence or history of clinically significant findings * History of febrile illness or mastitis within 5 days prior to the first dose of study medication * Participants who have received a COVID-19 vaccine within 7 days before screening or admission, or who are to be vaccinated with a COVID-19 vaccine at any time during the study confinement period * History of HIV infection, hepatitis B, or hepatitis C; positive testing for HIV, HBsAg, or HCVAb. Hepatitis B vaccination is allowed * Ab…