An observational study in COVID-19, sponsored by Pfizer. Completed at 1 site in Bahrain. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-08-19.
Sponsored by Pfizer · Observational
The purpose of this study is to collect information on the:
This study will be conducted in the Kingdom of Bahrain. The study will capture information of the adult COVID-19 outpatients and inpatients who have been prescribed nirmatrelvir, ritonavir treatment and those not treated with nirmatrelvir, ritonavir.
This study will have about 3000 patients treated with Paxlovid™ therapy and 1000 were not. The study will involve collection of patient information from medical records. The information collected can be either from papers or from computers.
The study will include patient information of those who:
7,990 studies on the registry are indexed under COVID-19; 466 are open to participants now.
This study's enrollment of 3,011 is above the median of 268 across 3,208 observational studies indexed under COVID-19.
Browse COVID-19 studies →Pfizer is the lead sponsor of 3,334 studies on the registry; 149 are open to participants now.
Of its 601 completed or terminated interventional studies of FDA-regulated products, 391 (65%) have results posted.
Counted across the registry records on this site, refreshed daily.
This will be a retrospective observational cohort study of patients diagnosed with COVID-19 in the Kingdom of Bahrain. Treated patients are defined as those have been prescribed nirmatrelvir, ritonavir and managed in the outpatient setting (eg, receiving medical treatment without being admitted to a hospital for COVID-19) while control group is those not treated with nirmatrelvir, ritonavir. Data will be from the I-Seha electronic medical records and descriptive analyses will be conducted for these two cohorts and will compare healthcare resource use in patients treated with nirmatrelvir, ritonavir and those not treated with nirmatrelvir, ritonavir.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Patients must meet all of the following inclusion criteria to be eligible for inclusion in the study:Age 18 years and older Patients with a diagnosis of COVID-19 whose information can be extracted from the I-Seha database
Exclusion Criteria:
There are no exclusion criteria for this study.
Adult COVID-19 patients' Healthcare Resource Utilization (HRU) within the 30-day period following nirmatrelvir, ritonavir prescription.
Drug: nirmatrelvir, ritonavir
Adults COVID-19 patient HRU within 30 days period following nirmatrelvir/ritonavir prescription
Other: Controls
Patients receiving Nirmatrelvir; Ritonavir (PAXLOVID)
Patients who do not receive Nirmatrevir/ritonavir (Paxlovid)
Number of Participants Classified Based on Education
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
Time frame: Baseline; from available retrospective data evaluated during 2 months of this study
Number of Participants Classified Based on Employment Status
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
Time frame: Baseline; from available retrospective data evaluated during 2 months of this study
Height
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
Time frame: Baseline; from available retrospective data evaluated during 2 months of this study
Weight
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
Time frame: Baseline; from available retrospective data evaluated during 2 months of this study
Body Mass Index (BMI)
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
Time frame: Baseline; from available retrospective data evaluated during 2 months of this study
Number of Participants Classified Based on Smoking Status
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
Time frame: Baseline; from available retrospective data evaluated during 2 months of this study
Number of Participants With at Least 1 Pre-existing Comorbidities
Pre-existing comorbidities included: asthma, emphysema, chronic obstructive pulmonary disease (COPD), hypertension, diabetes, obesity, cerebrovascular disease, neurological disease, chronic kidney disease, chronic liver disease, malignancy. Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
Time frame: Baseline; from available retrospective data evaluated during 2 months of this study
Number of Participants Who Took at Least 1 Concomitant Medications for Pre-existing Comorbidities
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
Time frame: Baseline; from available retrospective data evaluated during 2 months of this study
Number of Participants Who Used Antibiotics
Time frame: Up to 24 months following COVID-19 diagnosis; from available retrospective data evaluated during 2 months of this study
Number of Participants With Hospitalization for Any Cause
Time frame: Up to 24 months following COVID-19 diagnosis; from available retrospective data evaluated during 2 months of this study
Number of Participants With Intensive Care Unit (ICU) Admission for Any Cause
Time frame: Up to 24 months following COVID-19 diagnosis; from available retrospective data evaluated during 2 months of this study
Number of Participants Classified According to Length of Stay (LOS) in ICU for Any Cause
Time frame: Up to 24 months following COVID-19 diagnosis; from available retrospective data evaluated during 2 months of this study
Number of Participants With Yes/no Questionnaire on Outpatient Visits
Time frame: Up to 24 months following COVID-19 diagnosis; from available retrospective data evaluated during 2 months of this study
Number of Participants With Emergency Room (ER) Visits for Any Cause
Time frame: Up to 24 months following COVID-19 diagnosis; from available retrospective data evaluated during 2 months of this study
Number of Participants With Supplemental Oxygen Usage
Time frame: Up to 24 months following COVID-19 diagnosis; from available retrospective data evaluated during 2 months of this study
Number of Participants With Vasopressor Use
Time frame: Up to 24 months following COVID-19 diagnosis; from available retrospective data evaluated during 2 months of this study
Number of Participants Who Used Invasive Mechanical Ventilation (IMV)
Time frame: Up to 24 months following COVID-19 diagnosis; from available retrospective data evaluated during 2 months of this study
Data of eligible participants diagnosed with corona virus disease 2019 (COVID-19) in the Kingdom of Bahrain who were offered Paxlovid (nirmatrelvir, ritonavir) treatment between 16 February 2022 to 30 November 2022 (9.5 months) was included in this retrospective observational study. Data was retrieved from Kingdom of Bahrain national health information system \[(I-Seha electronic health records (EHR)\].
| Milestone | Treated With Paxlovid | Not Treated With Paxlovid |
|---|---|---|
| Started | 2005 | 1006 |
| Completed | 2005 | 1006 |
| Not completed | 0 | 0 |
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
No measurements were reported for this outcome.
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
No measurements were reported for this outcome.
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
No measurements were reported for this outcome.
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
No measurements were reported for this outcome.
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
| Kilogram over meter square (Kg/m^2) | Treated With Paxlovid | Not Treated With Paxlovid |
|---|---|---|
| Body Mass Index (BMI) | 29 (25 to 33) | 29 (25 to 34) |
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
No measurements were reported for this outcome.
Pre-existing comorbidities included: asthma, emphysema, chronic obstructive pulmonary disease (COPD), hypertension, diabetes, obesity, cerebrovascular disease, neurological disease, chronic kidney disease, chronic liver disease, malignancy. Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
| Participants | Treated With Paxlovid | Not Treated With Paxlovid |
|---|---|---|
| Number of Participants With at Least 1 Pre-existing Comorbidities | 1709 | 920 |
Baseline was defined as one year before the index date. Index date was Paxlovid prescription written date or dispense date; if neither of them were available, the COVID-19 diagnosis date was used as the index date.
No measurements were reported for this outcome.
| Participants | Treated With Paxlovid | Not Treated With Paxlovid |
|---|---|---|
| For any cause | 530 | 320 |
| For COVID-19 | 118 | 103 |
| Participants | Treated With Paxlovid | Not Treated With Paxlovid |
|---|---|---|
| Number of Participants With Hospitalization for Any Cause | 137 | 123 |
| Participants | Treated With Paxlovid | Not Treated With Paxlovid |
|---|---|---|
| Number of Participants With Intensive Care Unit (ICU) Admission for Any Cause | 3 | 1 |
| Participants | Treated With Paxlovid | Not Treated With Paxlovid |
|---|---|---|
| 3 Days | 0 | 1 |
| 6 Days | 1 | 0 |
| Missing | 2 | 0 |
No measurements were reported for this outcome.
| Participants | Treated With Paxlovid | Not Treated With Paxlovid |
|---|---|---|
| Number of Participants With Emergency Room (ER) Visits for Any Cause | 298 | 155 |
| Participants | Treated With Paxlovid | Not Treated With Paxlovid |
|---|---|---|
| Number of Participants With Supplemental Oxygen Usage | 21 | 11 |
No measurements were reported for this outcome.
| Participants | Treated With Paxlovid | Not Treated With Paxlovid |
|---|---|---|
| Number of Participants Who Used Invasive Mechanical Ventilation (IMV) | 0 | 1 |
Collected over All-cause mortality for both the reporting groups: up to 24 months following COVID-19 diagnosis and adverse events only for "Treated with Paxlovid" group: at Day 5 post Paxlovid course completion; from available retrospective data evaluated during 2 months of this study. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Treated With Paxlovid | 0/2,005 (0%) | 0/2,005 (0%) | 1,427/2,005 (71.2%) |
| Not Treated With Paxlovid | 0/1,006 (0%) | — | — |
| Event | Treated With Paxlovid | Not Treated With Paxlovid |
|---|---|---|
| Impaired sense of taste / BitternessGeneral disorders | 1214/2005 | — |
| DiarrheaGeneral disorders | 365/2005 | — |
| Muscle achesGeneral disorders | 88/2005 | — |
| Stomach/Abdominal painGeneral disorders | 47/2005 | — |
| Nausea/VomitingGeneral disorders | 44/2005 | — |
| HeadacheGeneral disorders | 15/2005 | — |
| DizzinessGeneral disorders | 8/2005 | — |
| ItchingGeneral disorders | 7/2005 | — |
| Neck/Back PainGeneral disorders | 7/2005 | — |
| CoughGeneral disorders | 5/2005 | — |
| Age, Customized(Participants) | Treated With Paxlovid | Not Treated With Paxlovid | Total |
|---|---|---|---|
| Age — 12-17 Years | 2 | 0 | 2 |
| Age — 18-29 Years | 457 | 204 | 661 |
| Age — 30-49 Years | 453 | 208 | 661 |
| Age — 50-64 Years | 485 | 201 | 686 |
| Age — 65-74 Years | 459 | 189 | 648 |
| Age — Greater than equal to 75 Years | 149 | 204 | 353 |
| Sex: Female, Male(Participants) | Treated With Paxlovid | Not Treated With Paxlovid | Total |
|---|---|---|---|
| Female | 1,005 | 489 | 1494 |
| Male | 1000 | 517 | 1517 |
| Race/Ethnicity, Customized(Participants) | Treated With Paxlovid | Not Treated With Paxlovid | Total |
|---|---|---|---|
| Ethnicity — Arab | 1,668 | 916 | 2584 |
| Ethnicity — Asian | 291 | 79 | 370 |
| Ethnicity — Black/African/Caribbean | 8 | 3 | 11 |
| Ethnicity — Mixed/Multiple Ethnic Groups | 16 | 3 | 19 |
| Ethnicity — Persian | 1 | 0 | 1 |
| Ethnicity — White | 21 | 5 | 26 |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: 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.
Ran from Mar 2024 to primary completion in May 2024, 2 months.
Results were first posted in Aug 2025, 1 year 3 months after primary completion.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Aug 2025. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.