Reinfection Rates Among Patients Who Previously Tested Positive for Coronavirus Disease 2019: A Retrospective Cohort Study

  1. Megan M Sheehan
  2. Anita J Reddy
  3. Michael B Rothberg

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Abstract

Background

Protection afforded from prior disease among patients with coronavirus disease 2019 (COVID-19) infection is unknown. If infection provides substantial long-lasting immunity, it may be appropriate to reconsider vaccination distribution.

Methods

This retrospective cohort study of 1 health system included 150 325 patients tested for COVID-19 infection via polymerase chain reaction from 12 March 2020 to 30 August 2020. Testing performed up to 24 February 2021 in these patients was included. The main outcome was reinfection, defined as infection ≥90 days after initial testing. Secondary outcomes were symptomatic infection and protection of prior infection against reinfection.

Results

Of 150 325 patients, 8845 (5.9%) tested positive and 141 480 (94.1%) tested negative before 30 August. A total of 1278 (14.4%) positive patients were retested after 90 days, and 62 had possible reinfection. Of those, 31 (50%) were symptomatic. Of those with initial negative testing, 5449 (3.9%) were subsequently positive and 3191 of those (58.5%) were symptomatic. Protection offered from prior infection was 81.8% (95% confidence interval [CI], 76.6–85.8) and against symptomatic infection was 84.5% (95% CI, 77.9–89.1). This protection increased over time.

Conclusions

Prior infection in patients with COVID-19 was highly protective against reinfection and symptomatic disease. This protection increased over time, suggesting that viral shedding or ongoing immune response may persist beyond 90 days and may not represent true reinfection. As vaccine supply is limited, patients with known history of COVID-19 could delay early vaccination to allow for the most vulnerable to access the vaccine and slow transmission.

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  1. Version published to 10.1093/cid/ciab234
  2. ScreenIT

    SciScore for 10.1101/2021.02.14.21251715: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board StatementIRB: This work was approved by Cleveland Clinic’s Institutional Review Board (IRB 20-1328).
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

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  3. Version published to 10.1101/2021.02.14.21251715v1 on medRxiv