Fig 4. Dependency of findings on vaccine function.

(A) A continuum of combinations of σ, the reduction of infections among vaccinated, and δ, the reduction of symptomatic infections among vaccinated infected individuals, can lead to a vaccine effectiveness of 50%, 75% or 90%. (B) Total deaths (y-axis) under a variety of scenarios, assuming a vaccine effectiveness of 90% and the use of the CDC allocation strategy. Scenarios differ in the relative contribution of σ and δ to the vaccine effectiveness (x-axis, see (A)), and the relative contagiousness of vaccinated individuals (compared to non-vaccinated), specified by line type (dashed: 0%, solid: 50%, dotted: 100%). (C) For three different objectives, the optimal vaccine allocation strategies are compared between two vaccines of extreme function: a vaccine that solely prevents infections (σ = 90%, δ = 0%) and a vaccine that solely prevents symptoms among infected individuals ((σ = 0%, δ = 90%). Sub-populations (defined as in Table 2) that are allocated to a later (earlier) priority phase in the latter vaccine are indicated by ↑ (↓). S4 Table contains the specific phase assignments for each sub-population.