COVID-19NCT06085924
A Study to Learn About Effects of Living With COVID-19 and the Use of the Medicines Nirmatrelvir-Ritonavir in Treating COVID-19.
An observational study of COVID-19, run by Pfizer at 1 site in Taiwan.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 0 years and older
- Conditions the study is for
- COVID-19
- What is being tested?
- SoC and Disease description
- How many people
- 2,315,187 participants
- Where
- 1 siteTaiwan
- Study dates
- 7 Nov 2023to 28 Feb 2025
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 0 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
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.
Who may be able to join
- 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
- ≥12 years of age
- Have COVID-19 diagnosis with international classification of diseases (ICD) code between 01 January 2022 and 31 December 2022
Who cannot join
- Patients without COVID-19 diagnosis
- Cohort 2:
- Patients without COVID-19 diagnosis
Trial locations and contacts
1 site in 1 country.
About this study
Official title: 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.
Read more
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.
- Conditions
- COVID-19
- Being tested
- SoC, Disease description
- Keywords
- COVID-19, real world evaluation on COVID-19 burden
- Medical subject headings
- COVID-19
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SoCDrug
COVID-19 treatment as per government guidance
Disease descriptionOther
No intervention
| Study group | Role | What they receive |
|---|---|---|
| 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 Receives: Other: Disease description | |
| 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 Receives: Drug: SoC |
What is being measured
The primary outcome is the main question the study is designed to answer.
Cohort 1: Demographical Characteristics of Participants with a Diagnosis of COVID-19 That Required Intensive Care Unit (ICU)
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Required ICU
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Demographical Characteristics of Participants with a Diagnosis of COVID-19 That Did Not Require ICU
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a diagnosis of COVID-19 that did not require ICU
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Demographical Characteristics of Participants with a diagnosis of COVID-19 that required ICU
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Demographical Characteristics of Participants with a Diagnosis of COVID-19 That Required Ventillatory Support
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Required Ventillatory Support
Measured: 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
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Did Not Require Ventillatory Support
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Demographics of Participants with a Diagnosis of COVID-19 That Had a Fatal Outcome
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Had a Fatal Outcome
Measured: 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
Measured: 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
Measured: 01 January 2021 to 31 December 2021
Cohort 2: Characteristics Associated with Patients Receiving nirmatrelvir/ritonavir vs Patients Not Receiving nirmatrelvir/ritonavir
Measured: 01 January 2022 to 31 December 2022
Secondary outcomes (17)
Cohort 1: Demographics of Participants with a Diagnosis of COVID-19 That Required Hospital Admission
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Required Hospital Admission
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Demographics of Participants with a Diagnosis of COVID-19 That Did Not Require Hospital Admission
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Did Not Require Hospital Admission
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Incidence Proportion of ICU Admissions Among COVID-19 Patients Requiring Hospitalization Per Age Range
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Clinical Characteristics Associated to ICU Admission Among Hospitalized COVID-19 Patients
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Risk Factors Associated to ICU Admission Among Hospitalized COVID-19 Patients
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Clinical Characteristics Associated to Ventilatory Support Among Hospitalized COVID-19 Patients
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Risk Factors Associated to Ventilatory Support Among Hospitalized COVID-19 Patients
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Mortality Rate Associated to Ventilatory Support Among Hospitalized COVID-19 Patients
Measured: 01 January 2021 to 31 December 2021
Cohort 1: Average Length of Stay (LOS) of Hospitalized COVID-19 Patients
Measured: 01 January 2021 to 31 December 2021
Cohort 2: Incidence for severe COVID-19 Overall
Measured: 01 January 2022 to 31 December 2022
Cohort 2: Incidence for severe COVID-19 By Risk Group
Measured: 01 January 2022 to 31 December 2022
Cohort 2: Incidence for severe COVID-19 By Time Period
Measured: 01 January 2022 to 31 December 2022
Cohort 2: Relative Risk for severe COVID-19 Overall
Measured: 01 January 2022 to 31 December 2022
Cohort 2: Relative Risk for severe COVID-19 By Risk Group
Measured: 01 January 2022 to 31 December 2022
Cohort 2: Relative Risk for severe COVID-19 By Time Period
Measured: 01 January 2022 to 31 December 2022
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Oct 2023
- Study start7 Nov 2023
- Primary completion28 Feb 2025
- Study completion28 Feb 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for COVID-19Studies of the same condition, open and under way.
- More trials run by PfizerThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 2,315,187 participants (actual)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06085924
- Sponsor's protocol ID
- C4671061
- Other IDs
- NCT06085924
- Status last verified
- May 2026
- First submitted
- 16 Oct 2023
- Last updated
- 22 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No: 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.
Study at a glance
From the registry record, last updated by the sponsor on 22 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Real World Evaluation of COVID-19 Burden and Nirmatrelvir/Ritonavir in Taiwan Using National Health Insurance Research Database
- ClinicalTrials.gov ID
- NCT06085924
- Acronym / sponsor ID
- C4671061
- Conditions
- COVID-19
- Keywords
- COVID-19, real world evaluation on COVID-19 burden
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 2,315,187 participants (actual)
- Lead sponsor
- PfizerIndustry (pharma, biotech, devices)
- Study start
- 7 Nov 2023 (actual)
- Primary completion
- 28 Feb 2025 (actual)
- Study completion
- 28 Feb 2025 (actual)
- First posted
- 17 Oct 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Cohort 1 - Cases of patients registered in the databases of all ages | – | Other: Disease descriptionPatients with a diagnosis of COVID-19 infection between 01 January 2021 and 31 December 2021 |
| Cohort 2 - Cases of patients registered in the databases of ≥12 years of age | – | Drug: SoCHave COVID-19 diagnosis with international classification of diseases (ICD) code between 01 January 2022 and 31 December 2022 |
Who may qualify
- Ages
- 0 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- 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.
Key inclusion criteria (5 listed)
- 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
- ≥12 years of age
- Have COVID-19 diagnosis with international classification of diseases (ICD) code between 01 January 2022 and 31 December 2022
Key exclusion criteria (3 listed)
- Patients without COVID-19 diagnosis
- Patients without COVID-19 diagnosis
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| SoCCOVID-19 treatment as per government guidance | Drug | Cohort 2 - Cases of patients registered in the databases of ≥12 years of age |
| Disease descriptionNo intervention | Other | Cohort 1 - Cases of patients registered in the databases of all ages |
Primary outcome
Cohort 1: Demographical Characteristics of Participants with a Diagnosis of COVID-19 That Required Intensive Care Unit (ICU)
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Required ICU
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Demographical Characteristics of Participants with a Diagnosis of COVID-19 That Did Not Require ICU
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a diagnosis of COVID-19 that did not require ICU
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Demographical Characteristics of Participants with a diagnosis of COVID-19 that required ICU
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Demographical Characteristics of Participants with a Diagnosis of COVID-19 That Required Ventillatory Support
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Required Ventillatory Support
Time frame: 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
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Did Not Require Ventillatory Support
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Demographics of Participants with a Diagnosis of COVID-19 That Had a Fatal Outcome
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Had a Fatal Outcome
Time frame: 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
Time frame: 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
Time frame: 01 January 2021 to 31 December 2021
Cohort 2: Characteristics Associated with Patients Receiving nirmatrelvir/ritonavir vs Patients Not Receiving nirmatrelvir/ritonavir
Time frame: 01 January 2022 to 31 December 2022
17 secondary outcomes
Cohort 1: Demographics of Participants with a Diagnosis of COVID-19 That Required Hospital Admission
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Required Hospital Admission
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Demographics of Participants with a Diagnosis of COVID-19 That Did Not Require Hospital Admission
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Comorbidities of Participants with a Diagnosis of COVID-19 That Did Not Require Hospital Admission
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Incidence Proportion of ICU Admissions Among COVID-19 Patients Requiring Hospitalization Per Age Range
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Clinical Characteristics Associated to ICU Admission Among Hospitalized COVID-19 Patients
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Risk Factors Associated to ICU Admission Among Hospitalized COVID-19 Patients
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Clinical Characteristics Associated to Ventilatory Support Among Hospitalized COVID-19 Patients
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Risk Factors Associated to Ventilatory Support Among Hospitalized COVID-19 Patients
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Mortality Rate Associated to Ventilatory Support Among Hospitalized COVID-19 Patients
Time frame: 01 January 2021 to 31 December 2021
Cohort 1: Average Length of Stay (LOS) of Hospitalized COVID-19 Patients
Time frame: 01 January 2021 to 31 December 2021
Cohort 2: Incidence for severe COVID-19 Overall
Time frame: 01 January 2022 to 31 December 2022
Cohort 2: Incidence for severe COVID-19 By Risk Group
Time frame: 01 January 2022 to 31 December 2022
Cohort 2: Incidence for severe COVID-19 By Time Period
Time frame: 01 January 2022 to 31 December 2022
Cohort 2: Relative Risk for severe COVID-19 Overall
Time frame: 01 January 2022 to 31 December 2022
Cohort 2: Relative Risk for severe COVID-19 By Risk Group
Time frame: 01 January 2022 to 31 December 2022
Cohort 2: Relative Risk for severe COVID-19 By Time Period
Time frame: 01 January 2022 to 31 December 2022
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Jun 2026.
- To obtain contact information for a study center near you, click here.Link provided by the sponsor.
- Individual participant dataSharing planned: No. 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Pfizer CT.gov Call Center study director
Pfizer
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of COVID-19, run by Pfizer at 1 site in Taiwan.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 22 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Taiwan. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Cohort 1: Demographical Characteristics of Participants with a Diagnosis of COVID-19 That Required Intensive Care Unit (ICU) (time frame: 01 January 2021 to 31 December 2021). The study lists 14 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Jun 2026.