Assessing unused residual Pfizer-BioNTech COVID-19 vaccine: a community observational study

  1. Stephen Hubbard
  2. Rajlaxmi Bais

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Abstract

Worldwide morbidity and mortality associated with Covid-19 are severe and ongoing. The Pfizer-BioNTech vaccine is said to be up to 95% effective against severe disease or death. We were able to demonstrate that an additional 9.8% of COVID-19 vaccine doses could theoretically be given if the residual vaccine within the reconstituted Pfizer vials after six doses are extracted were used. This could be achieved by aseptically combining this excess vaccine from multiple vials to achieve full 0.3ml doses.

Methods

An observational study was conducted in April, 2021, at a mass vaccine site run by a community volunteer organization on Bainbridge Island, Washington. We measured the amount of Pfizer-BioNTech COVID-19 vaccine that was left in 172 vials after six doses had been withdrawn per Centers for Disease Control (CDC) protocol.

Results

A total of 30.68 ml of leftover vaccine was measured and discarded as medical waste. 1,036 doses were given from these vials. An extra 102 doses theoretically could have been given using the residual vaccine in the vials. This would have resulted in 9.8% additional doses of COVID-19 vaccine without requiring new vials.

Conclusion

The ability to combine solution from reconstituted Pfizer vaccine vials to minimize waste and obtain additional doses of vaccine could result in an increase in the number of individuals that could be vaccinated worldwide without additional cost. Further studies to validate our findings are warranted. Clinical trials to study the feasibility, safety and efficacy of protocols using this excess vaccine should be considered.

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  1. ScreenIT

    SciScore for 10.1101/2021.08.03.21261569: (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

    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:
    One limitation of this study is the small sample size. However, given the uniformity of this mass-produced vaccine, our findings seem likely to apply to the Pfizer vaccine generally. Further trials are warranted to test our results. A second limitation is the fact that there still remained some unobtainable vaccine. Handlers were asked to record any excess vaccine that could be withdrawn after the sixth dose. However, there was an unknown amount of vaccine left in the vials that could not be removed with our syringes. Some of the vaccine seems to remain on the sides of the vial or in crevices around the stopper. Therefore, the amount of recoverable residual vaccine might be greater if better techniques were found to withdraw it. The clinical and financial impact of getting an extra 9.8% from the vaccine vials could be substantial. Pfizer says it expects to make enough for 3 billion shots in 2021. Pfizer has said it will make $26 billion in vaccine sales in 2021, which would make it the best-selling medicine ever. 9 President Biden recently announced the purchase of 500 million doses of Pfizer vaccine, much of which will presumably be used in vaccinations in the developing world. Combining and using the residual vaccine in the vials containing those doses could theoretically be used to give an extra 49 million doses at no extra cost. This is enough to vaccinate 24.5 million people. We recommend that clinical trials be started to test the feasibility, safety, and efficacy of us...

    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 10.1101/2021.08.03.21261569v1 on medRxiv