Breakthrough SARS-CoV-2 infections in 620,000 U.S. Veterans, February 1, 2021 to August 13, 2021

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Abstract

National data on COVID-19 vaccine breakthrough infections is inadequate but urgently needed to determine U.S. policy during the emergence of the Delta variant. We address this gap by comparing SARS CoV-2 infection by vaccination status from February 1, 2021 to August 13, 2021 in the Veterans Health Administration, covering 2.7% of the U.S. population. Vaccine protection declined by mid-August 2021, decreasing from 91.9% in March to 53.9% (p<0.01, n=619,755). Declines were greatest for the Janssen vaccine followed by Pfizer–BioNTech and Moderna. Patterns of breakthrough infection over time were consistent by age, despite rolling vaccine eligibility, implicating the Delta variant as the primary determinant of infection. Findings support continued efforts to increase vaccination and an immediate, national return to additional layers of protection against infection.

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  1. SciScore for 10.1101/2021.10.13.21264966: (What is this?)

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

    Table 1: Rigor

    EthicsIRB: This study was approved by the Institutional Review Board at the University of California San Francisco and the Public Health Institute, as well as the San Francisco VA Research and Development Committee.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    All analyses were conducted using SAS Enterprise Guide 7.1 (SAS Institute, Cary, NC).
    SAS Institute
    suggested: (Statistical Analysis System, RRID:SCR_008567)

    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:
    Our results should be interpreted in the context of limitations. We required a recent RT-PCR assay to be included in the analysis, and there may be differences in testing intervals and frequency by vaccination status. It is also likely that requiring a recent RT-PCR assay does not capture asymptomatic infections, during which testing may not be obtained. Our sample has proportionately fewer women, although a large number are still included. We did not have information on genotyping of infections to determine the proportion caused by the Delta variant. Finally, there is a delay between infection and hospitalization and death that is not captured by the urgency of this report. In summary, although vaccination remains protective against SARS-CoV-2 infection, this protection is waning as the Delta variant has emerged in the U.S. It is not yet clear whether reductions in vaccine protection against infection will translate into similar reductions in protection against hospitalization and death. COVID-19 vaccines remain the most important tool to prevent infection, severe illness, and death, but vaccines should be accompanied by additional measures, including masking, hand washing, physical distancing, and other public health interventions, in the face of increased risk of infection due to the Delta variant.

    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.