Dynamic strategy prioritising COVID-19 vaccines for seniors, essential workers offers greatest public health benefit


California: Given the limited supply of vaccines amid a surge in coronavirus cases worldwide, a dynamic strategy that prioritises who gets vaccinated for Covid-19 can save lives and reduce the spread of infections and deaths, according to a new study.
Debates rage on about prioritizing groups of people for vaccination even as there is a universal agreement that older people should get the vaccine first.
A study published in the journal PNAS from the University of California, Davis illustrates how optimal prioritization is sensitive to several factors, most notably, vaccine effectiveness and supply, rate of transmission, and the magnitude of initial infections.
A model incorporating epidemiological characteristics of COVID-19 and vaccine distribution strategies that selectively prioritize minimizing infections, years of life lost, or deaths finds that a dynamic vaccine prioritization strategy aids public health objectives and that, depending on the objective, essential workers may be prioritized to control disease spread or seniors may be prioritized to minimize deaths.
Senior author Michael Springborn, a UC Davis professor in the Department of Environmental Studies said the study assesses the optimal allocation of a limited vaccine supply in the United States across groups differentiated by age and essential worker status, which constrains opportunities for social distancing.
For the study, the researchers modelled COVID-19 transmission rates and the optimal allocation of an initially limited vaccine supply in the U.S. under a variety of scenarios. They found that deaths, years of life lost and infections were between 17 to 44 per cent lower when vaccinations targeted vulnerable populations — particularly seniors and essential workers — rather than an alternative approach where everyone is equally likely to be vaccinated.
When focusing on mortality, vaccination of older essential workers and ages 60 plus was almost always a top priority (i.e., targeted in the first 30 per cent of the population vaccinated). Alternatively, when infections are minimized, essential workers are prioritized, followed by school-age children, across a range of likely scenarios. We find that prioritization can substantially improve public health outcomes–31 to 40 per cent in the base scenario, relative to untargeted vaccination.
It was found that 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,
The study concludes that prioritizing essential workers versus seniors depends on conditions. For instance, when there is a good supply of effective vaccines and the outbreak is relatively under control, targeting essential workers first to help reduce overall spread can be ideal. But if vaccine supply is limited and cases and deaths are surging, targeting seniors and the most vulnerable directly may be the better strategy.
Gerardo Chowell of Georgia State University, Atlanta along with Michael R Springborn and Jack H Buckner of the University of California, Davis, are the authors in the study. (ANI)