Prioritizing who receives the limited supply of COVID-19 vaccines available saves lives and reduces spread of infection, a new study shows.

While there is mostly universal agreement that older people should get priority, debates are currently underway about prioritizing COVID-19 vaccines for a variety of other groups. Still others argue against targeting at all.

“Prioritization has benefits because people differ in at least two key ways—their risk of infection and the likelihood of serious consequences from infection,” says senior author Michael Springborn, a professor in the environmental studies and policy department at the University of California, Davis and an economist focused on environmental risk, including infectious disease.

“We know that front-line essential workers have less capacity to socially distance and thus an elevated risk, while seniors are more seriously impacted by infection. Accounting for this substantially increases the benefits of vaccination.”

For the study in the Proceedings of the National Academy of Sciences, researchers modeled COVID-19 transmission rates and the optimal allocation of an initially limited vaccine supply in the US under a variety of scenarios.

They found that deaths, years of life lost, and infections were between 17 to 44% lower when vaccinations targeted vulnerable populations—particularly seniors and essential workers—rather than an alternative approach where everyone is equally likely to be vaccinated.

“We also found that in regions where there was a faster increase in infections, and where there is less masking and social distancing occurring, targeting was even more important in avoiding those outcomes,” says lead author Jack Buckner, a PhD candidate in the UC Davis Graduate Group in Ecology.

Building on the standard approach in modeling analyses to account for age groups, the study is the first to include front-line essential workers as their own category. In doing so, the researchers identified that such workers should have vaccination priority along with or shortly after seniors. Policies that target based on both age and essential worker status substantially outperformed those that consider age only.

Read the full article about vaccine priority by Kat Kerlin at Futurity.