With COVID-19 vaccine production increasing rapidly and a growing stockpile of vaccine doses, the question is how to best use them. Countries are experimenting with different vaccine prioritization strategies, depending on their needs, population demographics, underlying contact structure and health system capacity.
Vaccination of frontline healthcare workers, residents of long-term care facilities and other priority groups is essential to achieving herd immunity, but it can take time. Using available vaccines more effectively, by vaccinating younger adults sooner and by avoiding over-vaccinating older adults, can reduce cases, deaths and hospitalizations (and, thus, the burden on health systems) and minimize adverse events.
But deciding on an optimal vaccine rollout strategy is not simple, given the current limited supply of vaccines. Bubar et al have developed five different vaccination scenarios that differ by age group, and have compared their effects on transmission rates and hospitalizations. Their models show that vaccinating the 80+ age group first is unlikely to prevent the spread of disease to the point where hospital capacity can be overwhelmed, and that it is therefore better from a health utility perspective to vaccinate essential workers earlier.