A new take on optimal vaccine prioritization: when age-based strategy is efficient?

"The rapid spread, high mortality rate, and hospital overcrowding made the SARS-CoV-2 virus a significant challenge for humanity. The emergent situation urgently called for investments in vaccine development as a critical measure to mitigate this issue. However, the financial costs and time required for vaccine development posed considerable obstacles to achieving comprehensive vaccination coverage. Therefore, understanding the most effective immunization strategy was paramount to contain the virus’s spread and optimize resource allocation in public policies. Age-based prioritization was applied in many regions, and one of the objectives of this work is to study under which circumstances such a strategy is efficient. Our results show that age-based vaccination is a poor strategy for disease eradication, although it has a fair performance in diminishing the number of deaths. Furthermore, other schemes, such as PageRank-based immunization, are much better options in general. We believe these results are of relevance, not only for the past SARS-CoV-2 pandemic, but also for future epidemic outbreaks".