Constructing an ethical framework for priority allocation of pandemic vaccines

Abstract

Background: Allocation of scarce resources during a pandemic extends to the allocation of vaccines when they eventually become available. We describe a framework for priority vaccine allocation that employed a cross-disciplinary approach, guided by ethical considerations and informed by local risk assessment.

Methods: Published and grey literature was reviewed, and augmented by consultation with key informants, to collate past experience, existing guidelines and emerging strategies for pandemic vaccine deployment. Identified ethical issues and decision-making processes were also included. Concurrently, simulation modelling studies estimated the likely impacts of alternative vaccine allocation approaches. Assembled evidence was presented to a workshop of national experts in pandemic preparedness, vaccine strategy, implementation and ethics. All of this evidence was then used to generate a proposed ethical framework for vaccine priorities best suited to the Australian context.

Findings: Published and emerging guidance for priority pandemic vaccine distribution differed widely with respect to strategic objectives, specification of target groups, and explicit discussion of ethical considerations and decision-making processes. Flexibility in response was universally emphasised, informed by real-time assessment of the pandemic impact level, and identification of disproportionately affected groups. Model outputs aided identification of vaccine approaches most likely to achieve overarching goals in pandemics of varying transmissibility and severity. Pandemic response aims deemed most relevant for an Australian framework were: creating and maintaining trust, promoting equity, and reducing harmful outcomes.

Interpretation: Defining clear and ethically-defendable objectives for pandemic response in context aids development of flexible and adaptive decision support frameworks and facilitates clear communication and engagement activities.

Keywords: Pandemic vaccine; Priority populations; Vaccine allocation; Vaccine ethics.

Fig. 1

Epidemic curves with respect to vaccine timeliness. Epidemic curves depict the three pandemic impact scenarios evaluated, of differing transmissibility and severity. The vertical dashed line at six weeks indicates our ‘base case’ assumption of early vaccine availability, based on the alignment of this timepoint with the initial epidemic phase.

Fig. 2

Achievable harm reductions with direct and indirect vaccine strategies. For each of the pandemic scenarios evaluated, columns report the percentage of harmful outcomes (presentations, hospitalisations, deaths) achieved under direct (green) and indirect (brown) vaccine approaches, compared with those observed without vaccine. Note that axis values differ markedly, reflecting the substantial benefits achieved in the low transmission case, in stark contrast to the high transmission scenario. Note the different scales used for the Y-axes. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 3

Vaccine benefits by underlying risk status. By pandemic scenario, achievable reductions in hospitalisation incidence are reported separately for low-risk and high-risk individuals. Dashed horizontal lines depict outcomes in the absence of a vaccine, columns show the achieved incidence for either of direct or indirect vaccine strategies. Note the different scales used for the Y-axes.

Fig. 4

Impact of complete versus partial vaccine dosing. Columns report the percentage of hospitalisations observed for each vaccine strategy and pandemic scenario, compared with no vaccine. Best outcomes are observed where ‘1 dose’ only is needed for full protection. Where ‘2 doses’ are needed, provision of both results in better outcomes than administering only ‘1 of 2 doses’. Note the different scales used for the Y-axes.