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  1. SciScore for 10.1101/2020.06.26.20141085: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: Environmental sampling does not require Institutional Review Board (IRB) approval; however, the project was reviewed by the OHSU IRB and an IRB Exemption was granted for this work.
    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: We detected the following sentences addressing limitations in the study:
    There were several limitations to this study. First, samples were not evaluated for the presence of viable SARS-CoV-2 virus. Second, to prevent disruption of hospital operations, routine sampling of all AHUs was not possible, limiting temporal analysis. Third, the sample point of a filter or damper can only be representative of that sampling area and the porous nature of the filters may inhibit efficient specimen recovery. Lastly, this is a focused examination of one specific exposure factor and does not address several others (exposure routes, sampling conditions, viability) and should therefore only serve as part of the equation in understanding the overall exposure risk of SARS-CoV-2.

    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

    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.

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  2. Our take

    This was a descriptive, cross-sectional study, available as a preprint and thus not yet peer reviewed, that found that SARS-CoV-2 RNA (and potential live virus) was found in samples taken from air handling units at an Oregon hospital. Viral RNA was found in 14 out of 56 samples, with the most RNA found in pre-filters. Although the study did not directly test for the presence of live viral particles, the study still provides evidence of the potential for aerosolized transmission of SARS-CoV-2 through ventilation systems. Further research is needed to verify the presence of live viral RNA, as this has implications for viral transmission across multiple rooms.

    Study design


    Study population and setting

    Investigators collected 56 samples from three different air handling units (AHUs) at the Oregon Health and Science University Hospital in May and June 2020 to determine the presence of SARS-CoV-2 RNA. These AHUs were located in different parts of the building. Data collectors sampled pre-filters, final filters, and supply dampers and recorded the direction of air flow for the vents. The air units both collect air from outside air flow and recirculate air to multiple floors of the hospital. Data collectors sampled surfaces from both the return and supply air parts of the AHUs.

    Summary of main findings

    SARS-CoV-2 RNA was present in 14 out of 56 (25%) of the samples collected. RNA was found in 7 out of the 20 pre-filters (35%), 2 out of the 12 final filters (17%), and 5 out of the 24 supply air dampers (21%). The HVAC system cycles from the ward to the AHU and back to the ward between 90 seconds and five minutes. Though, investigators detected viral RNA among the samples, it is unknown if these were viable particles (i.e. able to cause infection if inhaled).

    Study strengths

    This study provides valuable information concerning the possibility of aerosolized transmission through ventilation systems.


    The study did not test for live viral particles of SARS-CoV-2 and thus it is not clear whether the particles found were viable to infect people. Furthermore, investigators were not able to perform sampling on a regulated schedule so that they would not interrupt hospital operations. Investigators also did not collect samples of the air flowing in and out of the AHUs in addition to sampling the surfaces on the AHUs.

    Value added

    This is one of the first studies to examine the presence of SARS-CoV-RNA in air handling units. The fact that investigators found the presence of viral RNA in the samples suggest potential transmission through ventilation systems. Since these AHUs recirculate are throughout multiple rooms in the building, people may be vulnerable to infection even if they are not in the same room as someone infected if the aerosolized viral particles are still viable once circulated through the AHUs.

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