COVID-19DOXY-COVIDNCT05445479
Retrospective Study for Identificatiopn of a Link Between Doxycycline and COVID-19 Treatment
An observational study of COVID-19, run by Nantes University Hospital.
Trial summary
A new coronavirus, the third documented animal-to-human passage, emerged in Wuhan , China in the last quarter of 2019. Acne patients on doxycycline escaped seasonal viruses, showing the interest of this antibiotic as a possible treatment against COVID-19. Read more about this study
- Who is it for?
- Ages 12 years and older
- Conditions the study is for
- COVID-19
- What is being tested?
- Doxycycline
- How many people
- 0 participants
- Where
- No sites listed yet
- Study dates
- 1 Jan 2022to 1 Jan 2022
- 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 12 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: Cases are patients with data in the Medicare databases for whom at least one dispensing of doxycycline is identified during the period from January 1, 2020, to December 1, 2021. Patients included as cases are all patients identified in the Assurance Maladie databases as having been reimbursed for at least one oral doxycycline dosage form during the period of interest.
Who may be able to join
- Male or female, ≥ 12 years old
- Affiliated with the French social security system or equivalent system
- Having been dispensed oral doxycycline at a dose of 100 mg between January 1, 2020 and November 30, 2021
Who cannot join
None listed.
About this study
Official title: Retrospective Study to Identify Whether Doxycycline in SARS-CoV-2 Infection Protects Against Progression to a Severe Form.
A new coronavirus, the third documented animal-to-human passage, emerged in Wuhan , China in the last quarter of 2019. Acne patients on doxycycline escaped seasonal viruses, showing the interest of this antibiotic as a possible treatment against COVID-19.
The antiviral action of tetracyclines can be explained by different mechanisms. First of all, tetracyclines are modulators of innate immunity by decreasing NF-B expression, inhibiting inflammatory cytokines such as TNF-α, IL-1β and IL-6, inflammatory granulomas and free radical release . This action is obtained at doses lower than those necessary to obtain an antibiotic effect. Another possible action of tetracyclines is their ability to chelate zinc from matrix metalloproteinases (MMPS). The coronavirus family is known to bind to host MMPs, particularly for viral survival. Their chelating activity may help inhibit SARS-CoV-2 infection by limiting its ability to replicate in the host. Finally, tetracyclines could have a direct action by inhibiting the replication of single-stranded RNA virus, such as the SARS-CoV-2 coronavirus.We therefore propose a larger comparative study using data from the French National Health Data System.
Read the detailed description
DOXY-COVID study is a national, observational, retrospective cohort study to compare the risk of severe COVID-19 in doxycycline-treated patients versus non-doxycycline-treated control patients (so-called case-cohort study).
The patient inclusion period corresponds to the main waves associated with the COVID-19 epidemic in France, i.e. from January 1, 2020 to November 30, 2021. Indeed, the time of data access, expected during 2022, would not allow reasonable follow-up of doxycycline-exposed patients from December 1, 2021.
Data of interest collected on these patients are requested over the period from January 1, 2016, through December 31, 2021:
- From January 1, 2016, in order to be able to define a pre-exposure phenotype over a follow-up period of at least 4 years in the French Health Insurance databases (period 2016-2019 inclusive)
- Until December 31, 2021, in order to have at least one month's hindsight on the risk of occurrence of severe forms of COVID-19
- Conditions
- COVID-19
- Being tested
- Doxycycline
- Keywords
- COVID-19, Doxycycline, Treatment
- Medical subject headings
- COVID-19
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
DoxycyclineDrug
Patient with doxycycline treatment during COVID-19 waves
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of hospitalization associated with COVID-19
Measured: January 1, 2020 to November 30, 2021
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Jul 2022
- Study start1 Jan 2022
- Primary completion1 Jan 2022
- Study completion1 Jan 2022 (estimated)
Why it stopped: Study Never Initiated
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 Nantes University HospitalThe 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
- Case-control
- Time perspective
- Retrospective
- Enrolment
- 0 participants (actual)
Sponsor and investigators
- Lead sponsor
- Nantes University Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05445479
- Sponsor's protocol ID
- AP_BD_001
- Acronym
- DOXY-COVID
- Status last verified
- Jun 2026
- First submitted
- 1 Jul 2022
- Last updated
- 24 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 24 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Retrospective Study to Identify Whether Doxycycline in SARS-CoV-2 Infection Protects Against Progression to a Severe Form.
- ClinicalTrials.gov ID
- NCT05445479
- Acronym / sponsor ID
- DOXY-COVID / AP_BD_001
- Conditions
- COVID-19
- Keywords
- COVID-19, Doxycycline, Treatment
- Study type
- Observational
- Recruitment status
- WithdrawnReason stopped: Study Never Initiated
- Enrolment
- 0 participants (actual)
- Lead sponsor
- Nantes University HospitalUniversity, hospital or other
- Study start
- 1 Jan 2022 (actual)
- Primary completion
- 1 Jan 2022 (actual)
- Study completion
- 1 Jan 2022 (estimated)
- First posted
- 6 Jul 2022 (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.
A new coronavirus, the third documented animal-to-human passage, emerged in Wuhan , China in the last quarter of 2019. Acne patients on doxycycline escaped seasonal viruses, showing the interest of this antibiotic as a possible treatment against COVID-19.
The antiviral action of tetracyclines can be explained by different mechanisms. First of all, tetracyclines are modulators of innate immunity by decreasing NF-B expression, inhibiting inflammatory cytokines such as TNF-α, IL-1β and IL-6, inflammatory granulomas and free radical release . This action is obtained at doses lower than those necessary to obtain an antibiotic effect. Another possible action of tetracyclines is their ability to chelate zinc from matrix metalloproteinases (MMPS). The coronavirus family is known to bind to host MMPs, particularly for viral survival. Their chelating activity may help inhibit SARS-CoV-2 infection by limiting its ability to replicate in the host. Finally, tetracyclines could have a direct action by inhibiting the replication of single-stranded RNA virus, such as the SARS-CoV-2 coronavirus.We therefore propose a larger comparative study using data from the French National Health Data System.
Detailed description
DOXY-COVID study is a national, observational, retrospective cohort study to compare the risk of severe COVID-19 in doxycycline-treated patients versus non-doxycycline-treated control patients (so-called case-cohort study).
The patient inclusion period corresponds to the main waves associated with the COVID-19 epidemic in France, i.e. from January 1, 2020 to November 30, 2021. Indeed, the time of data access, expected during 2022, would not allow reasonable follow-up of doxycycline-exposed patients from December 1, 2021.
Data of interest collected on these patients are requested over the period from January 1, 2016, through December 31, 2021:
- From January 1, 2016, in order to be able to define a pre-exposure phenotype over a follow-up period of at least 4 years in the French Health Insurance databases (period 2016-2019 inclusive)
- Until December 31, 2021, in order to have at least one month's hindsight on the risk of occurrence of severe forms of COVID-19
Study design
- Observational model
- Case-control
- Time perspective
- Retrospective
Who may qualify
- Ages
- 12 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Cases are patients with data in the Medicare databases for whom at least one dispensing of doxycycline is identified during the period from January 1, 2020, to December 1, 2021. Patients included as cases are all patients identified in the Assurance Maladie databases as having been reimbursed for at least one oral doxycycline dosage form during the period of interest.
Key inclusion criteria (3 listed)
- Male or female, ≥ 12 years old
- Affiliated with the French social security system or equivalent system
- Having been dispensed oral doxycycline at a dose of 100 mg between January 1, 2020 and November 30, 2021
Key exclusion criteria (0 listed)
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 |
|---|---|---|
| DoxycyclinePatient with doxycycline treatment during COVID-19 waves | Drug | – |
Primary outcome
Number of hospitalization associated with COVID-19
Time frame: January 1, 2020 to November 30, 2021
Results and safety
The study was withdrawn before enrolling participants, so there are no results.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Jun 2026.
- Individual participant dataSharing planned: No
Related trials for COVID-19
Recruiting
Home-Based Exercise Tele-Rehabilitation After COVID-19
Post SARS-CoV2 (COVID-19)
RecruitingObservational study
Cardiovascular Disease Progression in Survivors of Community Acquired Pneumonia and Lung Infection by Covid-19.
Pneumonia, Community-Acquired, COVID-19 Pneumonia
RecruitingPhase 3
A Clinical Study of Molnupiravir to Prevent Severe Illness From Coronavirus Disease 2019 (COVID-19) in People Who Are High Risk (MK-4482-023)
Coronavirus Disease (COVID-19)
Not yet recruitingPhase 1
Phase I Open-Label Safety Trial of Pembrolizumab for Neurological Post- Acute Sequelae of SARS-CoV-2 (PD1-PASC I)
Post-Acute COVID-19 Syndrome
Active, not recruitingPhase 1
A Safety and Immunogenicity Trial of OCU500, ChAd36 Vector Encoding SARS-CoV-2 Spike Vaccine Via Intranasal and Inhalational Routes in Previously Vaccinated Adults
COVID-19
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.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
An observational study of COVID-19, run by Nantes University Hospital.
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 3 inclusion and 0 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: withdrawn, as of the sponsor's last update on 24 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
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 was withdrawn before enrolling participants, so there are no results.
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?
Number of hospitalization associated with COVID-19 (time frame: January 1, 2020 to November 30, 2021). 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 24 Jun 2026; AzTrials last refreshed its copy on 7 Nov 2026.