A Study to Learn About Effects of Living With COVID-19 and the Use of the Medicines Nirmatrelvir-Ritonavir in Treating COVID-19.

Real World Evaluation of COVID-19 Burden and Nirmatrelvir/Ritonavir in Taiwan Using National Health Insurance Research Database

The purpose of this study is to learn about:

• effects of living with COVID-19 and
• how effective is nirmatrelvir-ritonavir in treating COVID-19.

This is a study of two groups of COVID-19 patients in Taiwan.

In Group 1 the below participants were included in the study:

• Patients of all ages.
• Patients who were confirmed to have COVID-19 infection between 01 January 2021 and 31 December 2021.
• Cases of patients registered in the databases.

In Group 2 the below participants were included in the study:

• Participants who are 12 years or older.
• Confirmed to have COVID-19 between 01 January 2022 and 31 December 2022.

Nirmatrelvir-ritonavir is taken by mouth and is used to treat COVID-19.

The study will look at:

• the nature of Covid-19 disease.
• as well as the experiences of people receiving the nirmatrelvir-ritonavir.

This study will help to:

• understand what type of patients will need to be admitted to hospitals.
• see severe results due to COVID 19 infection.
• have more knowledge on the use of nirmatrelvir/ritonavir on COVID-19.

Study Overview

• Status: Completed
• Conditions: COVID-19
• Intervention / Treatment: Other: Disease description; Drug: SoC

• Study Type: Observational
• Enrollment (Actual): 8252912

Contacts and Locations

Study Locations

• Taiwan
  • Taipei, Taiwan
    • Pfizer Taiwan

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Study data will be retrospectively collected from the National Health Insurance Research Database (NHIRD). The NHIRD is a nation-wide claims database in Taiwan, which contains anonymized patient-level claims data covering 99.9% of the entire 23 million Taiwanese population.

Description

Cohort 1:

Inclusion Criteria:

• Patients of all ages
• Patients with a diagnosis of COVID-19 infection between 01 January 2021 and 31 December 2021
• Cases of patients registered in the databases

Exclusion Criteria:

• Patients without COVID-19 diagnosis

Cohort 2:

Inclusion Criteria:

• ≥12 years of age
• Have COVID-19 diagnosis with international classification of diseases (ICD) code between 01 January 2022 and 31 December 2022

Exclusion Criteria:

• Patients without COVID-19 diagnosis

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Cohort 1 - Cases of patients registered in the databases of all ages; Patients with a diagnosis of COVID-19 infection between 01 January 2021 and 31 December 2021	Other: Disease description; No intervention
Cohort 2 - Cases of patients registered in the databases of ≥12 years of age; Have COVID-19 diagnosis with international classification of diseases (ICD) code between 01 January 2022 and 31 December 2022	Drug: SoC; COVID-19 treatment as per government guidance

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Cohort 1: Demographical Characteristics of Participants with a Diagnosis of COVID-19 That Required Intensive Care Unit (ICU)	01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Required ICU	01 January 2021 to 31 December 2021
Cohort 1: Demographical Characteristics of Participants with a Diagnosis of COVID-19 That Did Not Require ICU	01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a diagnosis of COVID-19 that did not require ICU	01 January 2021 to 31 December 2021
Cohort 1: Demographical Characteristics of Participants with a diagnosis of COVID-19 that required ICU	01 January 2021 to 31 December 2021
Cohort 1: Demographical Characteristics of Participants with a Diagnosis of COVID-19 That Required Ventillatory Support	01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Required Ventillatory Support	01 January 2021 to 31 December 2021
Cohort 1: Demographical Characteristics of Participants with a Diagnosis of COVID-19 That Did Not Require Ventillatory Support	01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Did Not Require Ventillatory Support	01 January 2021 to 31 December 2021
Cohort 1: Demographics of Participants with a Diagnosis of COVID-19 That Had a Fatal Outcome	01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Had a Fatal Outcome	01 January 2021 to 31 December 2021
Cohort 1: Demographics of Participants with a Diagnosis of COVID-19 That Did Not Have a Fatal Outcome	01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Did Not Have a Fatal Outcome	01 January 2021 to 31 December 2021
Cohort 2: Characteristics Associated with Patients Receiving nirmatrelvir/ritonavir vs Patients Not Receiving nirmatrelvir/ritonavir	01 January 2022 to 31 December 2022

Secondary Outcome Measures

Outcome Measure	Time Frame
Cohort 1: Demographics of Participants with a Diagnosis of COVID-19 That Required Hospital Admission	01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Required Hospital Admission	01 January 2021 to 31 December 2021
Cohort 1: Demographics of Participants with a Diagnosis of COVID-19 That Did Not Require Hospital Admission	01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Did Not Require Hospital Admission	01 January 2021 to 31 December 2021
Cohort 1: Incidence Proportion of ICU Admissions Among COVID-19 Patients Requiring Hospitalization Per Age Range	01 January 2021 to 31 December 2021
Cohort 1: Clinical Characteristics Associated to ICU Admission Among Hospitalized COVID-19 Patients	01 January 2021 to 31 December 2021
Cohort 1: Risk Factors Associated to ICU Admission Among Hospitalized COVID-19 Patients	01 January 2021 to 31 December 2021
Cohort 1: Clinical Characteristics Associated to Ventilatory Support Among Hospitalized COVID-19 Patients	01 January 2021 to 31 December 2021
Cohort 1: Risk Factors Associated to Ventilatory Support Among Hospitalized COVID-19 Patients	01 January 2021 to 31 December 2021
Cohort 1: Mortality Rate Associated to Ventilatory Support Among Hospitalized COVID-19 Patients	01 January 2021 to 31 December 2021
Cohort 1: Average Length of Stay (LOS) of Hospitalized COVID-19 Patients	01 January 2021 to 31 December 2021
Cohort 2: Incidence for severe COVID-19 Overall	01 January 2022 to 31 December 2022
Cohort 2: Incidence for severe COVID-19 By Risk Group	01 January 2022 to 31 December 2022
Cohort 2: Incidence for severe COVID-19 By Time Period	01 January 2022 to 31 December 2022
Cohort 2: Relative Risk for severe COVID-19 Overall	01 January 2022 to 31 December 2022
Cohort 2: Relative Risk for severe COVID-19 By Risk Group	01 January 2022 to 31 December 2022
Cohort 2: Relative Risk for severe COVID-19 By Time Period	01 January 2022 to 31 December 2022

Collaborators and Investigators

• Sponsor: Pfizer
• Investigators: Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

Helpful Links

• To obtain contact information for a study center near you, click here.

Study record dates

Study Major Dates

• Study Start (Actual): November 7, 2023
• Primary Completion (Actual): February 28, 2025
• Study Completion (Actual): February 28, 2025

Study Registration Dates

• First Submitted: October 16, 2023
• First Submitted That Met QC Criteria: October 16, 2023
• First Posted (Actual): October 17, 2023

Study Record Updates

• Last Update Posted (Actual): November 25, 2025
• Last Update Submitted That Met QC Criteria: November 20, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: COVID-19; real world evaluation on COVID-19 burden
• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Lung Diseases; Pneumonia, Viral; Pneumonia; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; COVID-19
• Other Study ID Numbers: C4671061; NCT06085924 (Registry Identifier: ClinicalTrials.gov)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: 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.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No