Could Vaccine Dose Stretching Reduce COVID-19 Deaths?

67 Pages Posted: 29 Jun 2021 Last revised: 7 Jul 2021

See all articles by Witold Więcek

Witold Więcek

WAW Statistical Consulting Ltd.

Amrita Ahuja

Harvard University - Harvard Kennedy School (HKS)

Michael Kremer

Harvard University - Department of Economics; Brookings Institution; National Bureau of Economic Research (NBER); Center for Global Development; Harvard University - Harvard Kennedy School (HKS)

Alexandre Simoes Gomes

University of Chicago - Department of Economics

Christopher M. Snyder

Dartmouth College - Department of Economics; National Bureau of Economic Research

Alexander T. Tabarrok

George Mason University - Department of Economics; Mercatus Center

Brandon Tan

Harvard University

Multiple version iconThere are 3 versions of this paper

Date Written: June 12, 2021

Abstract

We argue that alternative COVID-19 vaccine dosing regimens could potentially dramatically accelerate global COVID-19 vaccination and reduce mortality, and that the costs of testing these regimens are dwarfed by their potential benefits. We first use the high correlation between neutralizing antibody response and efficacy against disease (Khoury et. al. 2021) to show that half or even quarter doses of some vaccines generate immune responses associated with high vaccine efficacy. We then use an SEIR model to estimate that under these efficacy levels, doubling or quadrupling the rate of vaccination by using fractional doses would dramatically reduce infections and mortality. Since the correlation between immune response and efficacy may not be fully predictive of efficacy with fractional doses, we then use the SEIR model to show that fractional dosing would substantially reduce infections and mortality over a wide range of plausible efficacy levels. Further immunogenicity studies for a range of vaccine and dose combinations could deliver outcomes in weeks and could be conducted with a few hundred healthy volunteers. National regulatory authorities could also decide to test efficacy of fractional dosing in the context of vaccination campaigns based on existing immune response data, as some did for delayed second doses. If efficacy turned out to be high, the approach could be implemented broadly, while if it turned out to be low, downside risk could be limited by administering full doses to those who had received fractional doses. The SEIR model also suggests that delaying second vaccine doses will likely have substantial mortality benefits for multiple, but not all, vaccine-variant combinations, underscoring the importance of ongoing surveillance. Finally, we find that for countries choosing between approved but lower efficacy vaccines available immediately and waiting for mRNA vaccines, using immediately available vaccines typically reduces mortality.

Note: Funding Statement: This work was supported in part by the Wellspring Philanthropic Fund (Grant No: 15104) and Open Philanthropy.

Declaration of Interests: Wi˛ecek provides scientific consultancy for Certara, a drug development company and 1 Day Sooner, a COVID-19 human challenge trial advocacy group. Wi˛ecek reports no material conflicts of interest with regards to development of COVID-19 vaccines. The other authors declare no competing interests.

Ethics Approval Statement: The data included in this research are publicly available.

Keywords: vaccine, pandemic, epidemiology, public health, supply

Suggested Citation

Więcek, Witold and Ahuja, Amrita and Kremer, Michael R. and Simoes Gomes, Alexandre and Snyder, Christopher M. and Tabarrok, Alexander T. and Tan, Brandon, Could Vaccine Dose Stretching Reduce COVID-19 Deaths? (June 12, 2021). University of Chicago, Becker Friedman Institute for Economics Working Paper No. 2021-68, Available at SSRN: https://ssrn.com/abstract=3864485 or http://dx.doi.org/10.2139/ssrn.3864485

Witold Więcek

WAW Statistical Consulting Ltd. ( email )

Amrita Ahuja

Harvard University - Harvard Kennedy School (HKS) ( email )

79 John F. Kennedy Street
Cambridge, MA 02138
United States

Michael R. Kremer (Contact Author)

Harvard University - Department of Economics ( email )

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United States

Brookings Institution

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National Bureau of Economic Research (NBER) ( email )

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Center for Global Development

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Harvard University - Harvard Kennedy School (HKS) ( email )

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Alexandre Simoes Gomes

University of Chicago - Department of Economics ( email )

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United States

Christopher M. Snyder

Dartmouth College - Department of Economics ( email )

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HOME PAGE: http://www.dartmouth.edu/~csnyder/

National Bureau of Economic Research ( email )

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Alexander T. Tabarrok

George Mason University - Department of Economics ( email )

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Mercatus Center ( email )

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Brandon Tan

Harvard University ( email )

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Cambridge, MA 02138
United States

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