Estimates of Single Dose and Full Dose BNT162b2 Vaccine Effectiveness among USAF Academy cadets, 1 Mar - 1 May 2021

  1. Douglas P. Wickert
  2. Erin A. Almand
  3. Kevin J. Baldovich
  4. Christopher A. Cullenbine
  5. Odaro J. Huckstep
  6. Joseph W. Rohrer
  7. John C. Sitko
  8. J. Jordan Steel
  9. Steven C.M. Hasstedt

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Abstract

Beginning in early March 2021 and continuing through May 2021, the USAF Academy began vaccinating cadets for protection against the SARS-CoV-2 virus with the BNT162b2 (Pfizer-BioNTech) mRNA vaccine. During this period, vaccination of the almost 4200 cadet population increased from 3% to 85% and prevalence of COVID-19 in the cadet population was constant at approximately 0.4% as indicated by weekly surveillance testing. In this study, vaccine effectiveness at preventing infection is estimated by comparing infection risk as a function of time since vaccination. A statistically significant four-fold reduction in infection risk was observed 14 days after the first vaccine dose and an eleven-fold reduction in infection risk was observed in fully vaccinated cadets. Overall, the Pfizer-BioNTech vaccine was 91% (95% confidence interval = 55-99%) effective at preventing infection in healthy young adults (17-26 years of age) in a university setting and military training environment.

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  1. ScreenIT

    SciScore for 10.1101/2021.07.28.21261138: (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

    Software and Algorithms
    SentencesResources
    All statistics were performed using the SciPy-Stats Python library.
    Python
    suggested: (IPython, RRID:SCR_001658)

    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 to the present study include potential variations in SARS-CoV-2 exposure risk during the time period. Weekly surveillance testing indicated approximately constant prevalence of COVID-19 during the analysis period, but surveillance testing was done with Sofia SARS Antigen Fluorescent Immunoassay which has a known low sensitivity (41%) when used for screening of asymptomatic persons [3]. A variation in exposure risk during the analysis period would alter infection risk as more of the cadet population was vaccinated over time. A second limitation is that the present analysis does not account for potential acquired immunity due to prior COVID-19 infections. Approximately 10-15% of the cadet population had previously tested positive for SARS-CoV-2 infection since May 2020, but since estimates for durable immunity are not available and cadets were vaccinated regardless of prior infection status, we did not account for prior infection in determining infection risk. A third limitation are prominent SARS-CoV-2 strains present during the study period. Based on random sequencing (approximately one-quarter of positive infection samples were sequenced), the B.1.429 strain was predominant (76%) at the beginning of the study period. The B.1.1.7 strain increased in prevalence during the study period. Both of two the breakthrough infections were B.1.1.7 variants. The Pfizer-BioNTech vaccine is effective against all known strains during the study period. The continuously developing...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We found bar graphs of continuous data. We recommend replacing bar graphs with more informative graphics, as many different datasets can lead to the same bar graph. The actual data may suggest different conclusions from the summary statistics. For more information, please see Weissgerber et al (2015).

    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 10.1101/2021.07.28.21261138 on medRxiv