COVID-19 TestingNCT05365750

COVID-19 Antibody and Reinfection Study

An observational study of COVID-19 Testing, run by Kaiser Permanente at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Trial summary

The goal of this study is to establish a cohort of Kaiser Permanente Colorado (KPCO) members who have and have not had COVID-19 infection for serial antibody testing and PCR testing to: 1. Quantify antibody titers among participants over 9 months. 2. Read more about this study

Who is it for?: Ages 18 years and olderHealthy volunteers can take part
Conditions the study is for: COVID-19 Testing
How many people: 4,235 participants
Where: 1 siteUnited States
Study dates: 15 Jun 2020to 31 Dec 2024
How long will I take part?: 10 Months
Phase: Observational
Are there results?: Yes, posted in the registrySummary in the doctors' view

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 18 years and older
All sexes
Healthy volunteers accepted
Adult, Older adult

Study population: The study cohort will include individuals who are enrolled in Kaiser Permanente Colorado's health plan. Individuals will be selected who have evidence of prior SARS CoV-2 infection and random samples of the general KPCO membership of similar demographic characteristics who appear not to have had SARS CoV-2 infection.

Inclusion criteria are Kaiser Permanente Colorado health plan members, with a valid email address or phone number in the electronic health record and not on the Do Not Call List for research.

Trial locations and contacts

1 site in 1 country.

United States1 site

Kaiser Permanente
Aurora, Colorado, 80014

Other trials in United States

About this study

The goal of this study is to establish a cohort of Kaiser Permanente Colorado (KPCO) members who have and have not had COVID-19 infection for serial antibody testing and PCR testing to:

Quantify antibody titers among participants over 9 months.
Determine the rates of asymptomatic, mild, and severe recurrent infection among participants with prior COVID-19.
Examine association between antibody titer levels and risk of recurrent infection using a case control analysis nested in the cohort.

Read the detailed description

In this study, the Kaiser Permanente Colorado (KPCO) Institute for Health Research (IHR) will evaluate SARS-CoV-2 IgG antibody titers over time among individuals with evidence of prior infection, and correlate antibody titers with risk of recurrent infection. The investigators will identify KPCO members who have and have not had prior infection, enroll them into a cohort study, conduct serial surveys for new COVID-19 symptoms, and facilitate serial viral and antibody testing.

All laboratory testing procedures and clinical management of participants will be conducted by KPCO operations. The research team will identify participants, obtain consent, administer surveys to assess COVID-19 symptoms, and direct patients to the appropriate testing. Health outcomes on cohort participants will be tracked with survey data on symptoms, clinical and utilization data from the KPCO electronic health record (e.g., hospitalization), and laboratory data (e.g., viral test results).

This research-operations partnership strategy will generate data to better understand the implications of positive antibody titers to this novel pathogen.

Conditions: COVID-19 Testing
Keywords: SARS-CoV-2

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Study groups in NCT05365750
Study group	Role	What they receive
Case		Case patients were drawn from a random sample of individuals who were enrolled in KPCO's health plan had suspected or confirmed SARS-CoV-2 infection and a random stratified sample of the general KPCO membership with similar age, gender, race/ethnicity and co-morbidities as case group. Within the cohort, case patients had a SARS-CoV-reinfection, defined as a positive SARS-CoV-2 RNA test ≥ 90 days after the first positive RNA test.
Control		Control patients were drawn from a random sample of individuals who were enrolled in KPCO's health plan had suspected or confirmed SARS-CoV-2 infection and a random stratified sample of the general KPCO membership with similar age, gender, race/ethnicity and co-morbidities as case group. Within the cohort, control patients had no evidence of a SARS-CoV-reinfection during the period of interest.

What is being measured

The primary outcome is the main question the study is designed to answer.

Reinfection With SARS-CoV-2
In this case-control analysis, case patients were participants with the outcome of reinfection. The date of reinfection was the index date. Control patients were those with a primary infection but without the outcome reinfection by the index date. The case and control participants were compared with respect to a seronegative test result (exposure) after primary infection and closest in time to the index date. Because the cases and controls were selected on the basis of the outcome, the seronegative result is listed below by case and control status.
Measured: Through the completion of the study analytic period, an average of 6 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

15 Jun 202031 Dec 2024

First posted9 May 2022
Study start15 Jun 2020
Primary completion30 Mar 2023
Study completion31 Dec 2024

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (1)Papers the sponsor has linked to this study.
Other trials for COVID-19 TestingStudies of the same condition, open and under way.
More trials run by Kaiser PermanenteThe 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: Prospective
Enrolment: 4,235 participants (actual)
Target duration: 10 Months

IDs, dates and publications

ClinicalTrials.gov ID: NCT05365750
Sponsor's protocol ID: 1589316-19
Status last verified: Aug 2025
First submitted: 5 May 2022
Last updated: 18 Sep 2025
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: No

Publications

Binswanger IA, Narwaney KJ, Barrow JC, Albers KB, Bechtel L, Steiner CA, Ann Shoup J, Glanz JM. Association between severe acute respiratory syndrome coronavirus 2 antibody status and reinfection: A case-control study nested in a Colorado-based prospective cohort study. Prev Med Rep. 2023 Dec 1;37:102530. doi: 10.1016/j.pmedr.2023.102530. eCollection 2024 Jan.
PubMed 38205171

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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All COVID-19 Testing trials

Study at a glance

From the registry record, last updated by the sponsor on 18 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: COVID-19 Antibody and Reinfection Study
ClinicalTrials.gov ID: NCT05365750
Acronym / sponsor ID: 1589316-19
Conditions: COVID-19 Testing
Keywords: SARS-CoV-2
Study type: Observational
Recruitment status: Completed
Enrolment: 4,235 participants (actual)
Lead sponsor: Kaiser PermanenteUniversity, hospital or other
Study start: 15 Jun 2020 (actual)
Primary completion: 30 Mar 2023 (actual)
Study completion: 31 Dec 2024 (actual)
First posted: 9 May 2022 (actual)
Results: Posted 18 Sep 2025

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

The goal of this study is to establish a cohort of Kaiser Permanente Colorado (KPCO) members who have and have not had COVID-19 infection for serial antibody testing and PCR testing to:

Quantify antibody titers among participants over 9 months.
Determine the rates of asymptomatic, mild, and severe recurrent infection among participants with prior COVID-19.
Examine association between antibody titer levels and risk of recurrent infection using a case control analysis nested in the cohort.

Detailed description

This research-operations partnership strategy will generate data to better understand the implications of positive antibody titers to this novel pathogen.

Study design

Observational model: Case-control
Time perspective: Prospective
Target follow-up: 10 Months
Number of arms: 2

Arm	Type	Receives
Case	–	–Case patients were drawn from a random sample of individuals who were enrolled in KPCO's health plan had suspected or confirmed SARS-CoV-2 infection and a random stratified sample of the general KPCO membership with similar age, gender, race/ethnicity and co-morbidities as case group. Within the cohort, case patients had a SARS-CoV-reinfection, defined as a positive SARS-CoV-2 RNA test ≥ 90 days after the first positive RNA test.
Control	–	–Control patients were drawn from a random sample of individuals who were enrolled in KPCO's health plan had suspected or confirmed SARS-CoV-2 infection and a random stratified sample of the general KPCO membership with similar age, gender, race/ethnicity and co-morbidities as case group. Within the cohort, control patients had no evidence of a SARS-CoV-reinfection during the period of interest.

Who may qualify

Ages: 18 years and older
Sex: All
Healthy volunteers: Accepted
Age groups: Adult, Older adult
Study population: The study cohort will include individuals who are enrolled in Kaiser Permanente Colorado's health plan. Individuals will be selected who have evidence of prior SARS CoV-2 infection and random samples of the general KPCO membership of similar demographic characteristics who appear not to have had SARS CoV-2 infection.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Primary outcome

Reinfection With SARS-CoV-2
Time frame: Through the completion of the study analytic period, an average of 6 months
In this case-control analysis, case patients were participants with the outcome of reinfection. The date of reinfection was the index date. Control patients were those with a primary infection but without the outcome reinfection by the index date. The case and control participants were compared with respect to a seronegative test result (exposure) after primary infection and closest in time to the index date. Because the cases and controls were selected on the basis of the outcome, the seronegative result is listed below by case and control status.

Results and safety

Results posted to the registry on 18 Sep 2025, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Case Patients Nested Within the Cohort	80	80
Control Patients Nested Within the Cohort	1,034	1,034

Primary outcome: Reinfection With SARS-CoV-2

Time frame: Through the completion of the study analytic period, an average of 6 months. Count of participants. Unit: Participants

Measure	Case Patients n = 80	Control Patients n = 1034
Seronegative test results	12	77
Seropositive test results	68	957

Population analysed: Study cohort members with a primary SARS-CoV-2 infection

Adverse events

Time frame: Through the completion of the study analytic period, an average of 6 months. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Case Patients Nested Within the Cohort	0 of 80 (0%)	0 of 80 (0%)	0 of 80
Control Patients Nested Within the Cohort	0 of 1,034 (0%)	0 of 1,034 (0%)	0 of 1,034

Limitations and caveats (from the sponsor): Adherence to the study's testing guidance was inconsistent. We encouraged regular on-site testing but may not have captured some home-based testing results. Variable sensitivity and specificity of different serologic tests could have influenced our results. Variable sero-reversion rates across tests could have been due to variable lengths of time between the primary infection and testing. The definition of a reinfection used could have identified viral persistence.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 18 Sep 2025.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Results publication: PubMed 38205171Binswanger IA, Narwaney KJ, Barrow JC, Albers KB, Bechtel L, Steiner CA, Ann Shoup J, Glanz JM. Association between severe acute respiratory syndrome coronavirus 2 antibody status and reinfection: A case-control study nested in a Colorado-based prospective cohort study. Prev Med Rep. 2023 Dec 1;37:102530. doi: 10.1016/j.pmedr.2023.102530. eCollection 2024 Jan.
PublicationLink provided by the sponsor.
Individual participant dataSharing planned: No

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COVID-19, Coronavirus Disease 2019
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SARS-CoV-2 Infection, Influenza A
Active, not recruiting
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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.

Ingrid Binswanger, MD, MPH, MS principal investigator

Kaiser Permanente

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 Testing, run by Kaiser Permanente at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

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 18 Sep 2025. 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 United States. 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?

Yes. Results are posted in the registry (first posted 18 Sep 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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?

Reinfection With SARS-CoV-2 (time frame: Through the completion of the study analytic period, an average of 6 months). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05365750, which also lists 1 linked publication.

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 18 Sep 2025.