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Review 1: "Optimizing Vaccine Allocation for COVID-19 Vaccines: Critical Role of Single-Dose Vaccination"

Published onMar 31, 2022
Review 1: "Optimizing Vaccine Allocation for COVID-19 Vaccines: Critical Role of Single-Dose Vaccination"

RR:C19 Evidence Scale rating by reviewer:

  • Strong. The main study claims are very well-justified by the data and analytic methods used. There is little room for doubt that the study produced has very similar results and conclusions as compared with the hypothetical ideal study. The study’s main claims should be considered conclusive and actionable without reservation.



The paper applies a mathematical model developed in the authors’ earlier work, to conduct a systematic analysis of optimal vaccine allocation, given a limited vaccine supply, and many uncertainties regarding its efficacy (single vs. double dose), and its action on disease severity and transmissibility. The authors employ SEIR methodology for age-structured populations, with different (asymptomatic, symptomatic) disease pathways, hospitalization, and identified population risk-groups. The latter motivates their setup for vaccine allocation schedules and strategies.

One of critical questions in many ongoing vaccination programs is how to achieve the best output (e.g. reduction of mortality), by using single-dose vaccination and larger coverage in exchange for a potentially lower level of protection. Specifically, they ask who should be vaccinated first, and how many doses should individuals in different risk groups receive. Given many uncertainties of the disease spread and control, the authors selected a reasonable set of model inputs and control parameters to identity optimal vaccine allocation strategies (single vs. double, coverage fraction et al) for different risk groups under different transmission environments. Their analysis covers a wide range of possibilities. While many simplifications were used in the modelling setup and vaccine implementation, the overall results appear to be robust. They could provide some useful insights for policy planning. So the paper makes a significant contribution to Covid modelling. I have no major comments.

A few minor comments/suggestions: All figures have to panel top panel made of light/dark blue that correspond to single/double vaccine efficacy, with fixed double (90%), and variable SDE. It would be useful if authors include it either in each figure caption, or as a general comment for all figures. Supplemental figures

p1: Figure S1 is missing

Fig S4: … 5–10% with two doses… Should be … 5–25% with two doses… (?)


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