Testing for SARS-CoV-2 among cruise ship travelers repatriated to the United States, February–March 2020

  1. Michelle A. Waltenburg
  2. Mary A. Pomeroy
  3. Laura Hughes
  4. Jeremy A.W. Gold
  5. Oren Mayer
  6. Arnold Vang
  7. Benjamin D. Hallowell
  8. Loretta Foster
  9. Kerui Xu
  10. Rita Espinoza
  11. Kristina Hsieh
  12. Emily G. Pieracci
  13. Gabriella Wuyke
  14. Juliana Da Silva
  15. R. Paul McClung
  16. Jonathan Steinberg
  17. Matthew Westercamp
  18. Snigdha Vallabhaneni
  19. Jessica Li
  20. Amy L. Valderrama
  21. George R. Grimes
  22. R. Reid Harvey
  23. Randall J. Nett
  24. Kindra Stokes
  25. Stephen Lindstrom
  26. Allison D. Miller
  27. Eric P. Griggs
  28. Jennifer L. Milucky
  29. Adam Bjork
  30. Valerie Albrecht
  31. Wendi L. Kuhnert
  32. Carolyn V. Gould
  33. Nancy W. Knight
  34. Noele P. Nelson
  35. Margaret A. Honein
  36. Casey Barton Behravesh
  37. CDC COVID-19 Investigation Team
  38. Christine L. Dubray
  39. Grace E. Marx

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Abstract

Background

In early 2020, an outbreak of coronavirus disease 2019 occurred among passengers and crew of the Diamond Princess cruise ship. During February 16–17, some US citizens, residents, and their partners voluntarily repatriated to the US from Japan.

Methods

We conducted a retrospective, longitudinal evaluation of repatriated travelers where the outcome of interest was a positive test for SARS-CoV-2. Travelers who tested positive for SARS-CoV-2 were isolated in hospitals or at home under county isolation orders and underwent serial testing by real-time reverse transcription polymerase chain reaction (RT-PCR) approximately every other day, as contemporaneous US guidance required two consecutive negative tests collected ≥24 hours apart and symptom improvement before release from isolation.

Results

Among quarantined repatriated travelers, 14% tested positive for SARS-CoV-2. One-fifth of infected travelers initially tested negative but were identified on subsequent testing. All infected travelers remained asymptomatic or developed mild symptoms during isolation. Many travelers remained in prolonged isolation because of persistent viral detection based on contemporaneous policies.

Conclusion

Our findings support testing within 3-5 days after possible SARS-CoV-2 exposure to comprehensively identify infections and mitigate transmission and lend support to symptom- and time-based isolation recommendations, rather than test-based criteria.

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  1. ScreenIT

    SciScore for 10.1101/2021.06.07.21258318: (What is this?)

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

    Table 1: Rigor

    Ethicsnot detected.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Experimental Models: Organisms/Strains
    SentencesResources
    Ct values for the N1 and N2 genetic markers were highly correlated (Appendix A); for simplicity, we reported Ct values for the N1 genetic marker.
    N2
    suggested: None

    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: We detected the following sentences addressing limitations in the study:
    Limitations of the study: Our analysis has several limitations. Our results are not likely to be representative of the general US population; our small sample size of repatriated travelers was generally older and did not include travelers with severe COVID-19 who were hospitalized in Japan. Comprehensive longitudinal symptom and laboratory data were not available for all travelers throughout isolation. Information on patient-related factors (e.g., underlying health conditions) that might have influenced persistent viral shedding or low Ct values was not available. Ct values can be influenced by test-related factors, including specimen quality, reaction conditions, and amplification efficiency [15]. Viral culture data are needed to demonstrate the presence of replication-competent virus to determine the duration of shedding of viable virus and implications for risk of transmission.

    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.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  2. Version published to 10.1101/2021.06.07.21258318v1 on medRxiv