Challenging the idea that older people with shorter life expectancies should rank lower in coronavirus immunisation efforts, University of California-Berkeley research shows that giving vaccine priority to those most at risk of dying from COVID-19 will save the maximum number of lives, and their potential or future years of life.
The findings address the ethical dilemma of who should be first in line for a limited supply of vaccine shots amid a contagion that so far has killed 500,000 in the US and 2.4m globally.
“Since older age is accompanied by falling life expectancy, it is widely assumed that means we’re saving fewer years of life,” said study lead author Joshua Goldstein, a UC Berkeley professor of demography.
“We show this to be mistaken,” he added. “The age patterns of COVID-19 mortality are such that vaccinating the oldest first saves the most lives and, surprisingly, also maximises years of remaining life expectancy.”
Taking age and health risks into account, Goldstein, UC Berkeley demographer Kenneth Wachter and Bucknell University mathematician Thomas Cassidy conducted an analysis of life expectancy in the US, Germany and South Korea in the face of the year-long coronavirus pandemic.
They based their calculations on the number of lives potentially saved from being vaccinated, multiplied by the life expectancy of those vaccinated. For example, if 1m vaccinations saved 1,000 lives, and those vaccinated people, on average, were projected to live another 20 years, the total number of years of life saved would be 20,000.
The mathematical arguments upon which they based their conclusion apply not just to a few countries, but generally around the globe, the researchers said.
“Allocating scarce COVID-19 vaccine doses involves many trade-offs. However, a conflict between minimising the count of deaths and maximising remaining life is not one of them,” Goldstein said.
Since the approval of various COVID vaccines last fall, and their rollouts in December, a debate has been mounting over which groups to inoculate first, given limited vaccine supplies and, in many cases, chaotic distribution systems.
While some groups have argued that essential workers should take priority to keep health, education and economic systems up and running, others, such as the World Health Organisation, have declined the “Years of Life Lost” criterion in ranking vaccine recipients due to older people’s disproportionately higher risk of death and the perception that such an approach would be discriminatory and disrespectful.
This latest study should assuage some of those concerns, researchers said.
“Our empirical analysis shows it is easier than thought to set such fears aside and to give vaccine priority to the oldest and those in the most vulnerable states of health,” according to the paper, which notes that COVID deaths rise exponentially with age.
The researchers found that the COVID death rate by age increased by about 11% per year of age in the US, Germany and Korea. Moreover, they found that vaccinating people in their 90s would save three times as many lives as giving the same doses to people in their 80s.
“Before this study, it was suspected that there would be some intermediate age – not too old and not too young – which would maximise the benefit of a vaccine, in terms of person years of life saved,” Goldstein said. “But surprisingly, we show this is not the case.”
Study details
Vaccinating the oldest against COVID-19 saves both the most lives and most years of life
Joshua R Goldstein, Thomas Cassidy, Kenneth W Wachte
Published in PNAS on 16 March 2021
Abstract
Many competing criteria are under consideration for prioritizing COVID-19 vaccination. Two criteria based on age are demographic: lives saved and years of future life saved. Vaccinating the very old against COVID-19 saves the most lives, but, since older age is accompanied by falling life expectancy, it is widely supposed that these two goals are in conflict. We show this to be mistaken. The age patterns of COVID-19 mortality are such that vaccinating the oldest first saves the most lives and, surprisingly, also maximizes years of remaining life expectancy. We demonstrate this relationship empirically in the United States, Germany, and South Korea and with mathematical analysis of life tables. Our age-risk results, under usual conditions, also apply to health risks.
[link url="https://news.berkeley.edu/2021/02/25/prioritizing-oldest-for-covid-19-vaccines-saves-more-lives-years-of-life/"]University of California-Berkeley material[/link]
[link url="https://www.pnas.org/content/118/11/e2026322118"]Proceedings of the National Academy of Sciences study (Open access)[/link]