A Study to Understand How the Use of Paxlovid Affected Healthcare Use in People With Pre-existing Conditions.

This is a cohort study that will include Paxlovid (nirmatrelvir-ritonavir) treatment eligible for people with a positive SARS-CoV-2 diagnostic test and at least one COVID-19 symptom. This study will look at the change in Post Covid Conditions measured by the number of outpatients, Emergency department, urgent care and inpatient visits before and after COVID-19 between those who did and did not receive Paxlovid. In addition, changes in frailty post-acute infection will be evaluated, in a separate analysis. It is hypothesized that individuals with COVID-19 who received Paxlovid will have a smaller post-COVID-19 increase (vs pre-COVID) in PCC healthcare utilization (i.e., cardiopulmonary) in comparison to patients with COVID-19 who did not receive Paxlovid.

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Key information

Conditions

COVID-19 Chronic Disease Coronaviridae Infections Coronavirus Infections Disease Attributes Infections Lung Diseases Nidovirales Infections Pathologic Processes Pathological Conditions, Signs and Symptoms Pneumonia Pneumonia, Viral Post-Acute COVID-19 Syndrome Post-Infectious Disorders RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Pfizer New York

New York, 10001, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Developed at least one COVID-19 symptom between Apr 1, 2022 through Dec 31, 2023
A positive lab-confirmed polymerase chain reaction (PCR) SARS-COV-2 test 5 days after symptom onset (primary analysis).
Continuous enrollment in KPSC health plans for at least 1 year (allowing for a 31-day gap to account for potential delays in membership renewal) before the date of symptom onset
Active membership in KPSC health plans for at least 31 days after the date of symptom onset
Eligible for nirmatrelvir-ritonavir defined by age and CDC-defined risk factors for severe COVID-19

Exclusion criteria

Individuals on another medication that is contraindicated for treatment with nirmatrelvir-ritonavir defined as having any prescription drug claim in the 90 days prior to COVID-19 symptom onset
Receipt of any COVID-19 antiviral (molnupiravir, remdesivir, nirmatrelvir/ritonavir) or monoclonal antibody treatment (bamlanivimab, bebtelovimab, casirivimab/imdevimab, cilgavimab/tixagevimab, otrovimab,) <180 days prior to COVID-19 symptom onset
Any positive SARS-CoV-2 test, including self-reported tests, <180 days prior to COVID-19 symptom onset.

Treatment and study plan

nirmatrelvir-ritonavir

Drug

Paxlovid standard of treatment care

Other names: Paxlovid

Primary outcomes

Cardio-pulmonary Measurement A: Change in rate of cardiopulmonary-related healthcare utilization in patients that received nirmatrelvir-ritonavir compared to not received.

Time frame: 180 days before COVID-19 symptoms to 180 days after or 365 days after

Secondary outcomes

Frailty Measurement A: Change in frailty measured by Frailty score Median (IQR) in patients that did receive in patients nirmatrelvir-ritonavir compared to not received.

Time frame: During Pre-period: 12 months prior to symptom onset Frailty score Median (IQR) to 12 months after.

Sponsors and collaborators

Lead sponsor

Pfizer

Industry

Registry information

Official study title

Impact of Nirmatrelvir-ritonavir on Changes in Healthcare Utilization and Frailty Following COVID-19: a Difference-in-difference Analysis

Important dates

Study start: 2025
Primary completion: 2025
Study completion: 2025
First posted: Jul 29, 2025
Registry last updated: Jul 29, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

Completed