In a recent study published in the journal Nature Human Behavior, researchers estimated life expectancy (LE) changes in 29 high- and middle-income countries since 2020, when the coronavirus disease 2019 (COVID-19) pandemic began.
Study: Life expectancy changes since COVID-19. Image Credit: ffikretow / Shutterstock
Background
Period LE is a measure of population health, a decline that indicates increased mortality. It is typically standardized based on age and commonly employed for international comparisons of population health.
The COVID-19 pandemic triggered a mortality shock resulting in unprecedented LE declines in 2020, not observed in the recent history of high-income countries, such as the United States (US) and England. Despite limited data availability for in-depth investigations, emerging evidence suggests even higher LE declines in low-to-middle-income countries, such as India and Latin America. On the other hand, some countries, such as Australia, Norway, Finland, and Denmark, did not witness any LE decline.
LE fluctuations are common; however, most are short-term, followed by quick bouncebacks. However, the COVID-19-induced LE shocks are global and still ongoing. Moreover, emerging estimates suggest that the US and Russia will continue to witness further LE declines as the impact of the pandemic turns heterogeneous across populations. Some factors influencing the pandemic's course encompass prior infections, non-pharmaceutical interventions (NPIs), and vaccination uptake.
About the study
In the present study, researchers estimated LE changes in 29 countries since 2019 using all-cause mortality data from the Short-Term Mortality Fluctuations Database deploying a previously validated methodology. The study analysis covered the total population, including males and females.
Using decomposition techniques, they stratified mortality changes by age group and compared annual LE changes and deficits with historic year-to-year mortality data (raw). In this way, they determined to what extent registered COVID-19 deaths contributed to recent trends and deficits in LE. Specifically, they compared the magnitude and length of the current global LE decline with other significant mortality shocks during the 20th century. Lastly, the team evaluated the associations between LE changes and vaccination uptake.
Study findings
The COVID-19 pandemic triggered mortality increases and subsequent period LE declines of unprecedented scale by the end of 2020. In 2021, even those countries performing well previously lagged behind their LE projections due to the increased continuation of pre-pandemic trends. Nevertheless, countries like Switzerland, Belgium, Sweden, and France bounced back from their 2020 LE losses in 2021. They reverted mortality among 60+ people to pre-pandemic levels without shifting the mortality burden to younger age groups.
Finland, Norway, and Denmark remarkably maintained pre-pandemic LE levels throughout 2020 and 2021. They achieved this unbeatable feat by delivering COVID-19 vaccines faster than the whole of the European Union. Also, they ensured their healthcare system worked effectively at a high baseline capacity.
Reversion to pre-pandemic LE levels indicates a normalization of the mortality risk. However, it does not help regain the loss of life years during declining LE periods. Sweden, for instance, suffered a substantial LE loss in 2020 and gained pre-pandemic LE levels in 2021. Further, the researchers noted marked differences in 2021 LE deficits in eastern Europe than in the West, most likely because of lower vaccination rates in east Europe.
The increasing mortality below age 60 in the US contributed the most to LE losses in 2020 and 2021. Since COVID-19-unrelated mortality (e.g., drug overdose) also increased in these age groups, it pointed to the perpetuation and deterioration of a previous mortality crisis among younger adults in the US. In addition, age-based differences in vaccine uptake in the US might have added to the shift to mortality in younger age groups. As per the US Centers for Disease Control and Prevention (CDC) data, 82.3% of 65- to 74-year-olds were fully vaccinated in the US compared to 66.9% of 50- to 64-year-olds. It means vaccination better protected the older US population during the Delta wave of summer/autumn 2021.
The shift towards higher mortality in younger age groups reflects differences in vaccine protection, behavioral responses, or deaths from indirect causes. However, these factors are not yet fully understood. Likewise, it remains unclear why there were lower-than-expected deaths in 2021 in Belgium, England, France, and Slovenia due to COVID-19-unrelated reasons.
Conclusion
Humans have faced multiple mortality crises during the twentieth century, yet LE increased globally, especially in the second half of the century. However, COVID-19 triggered the most severe global mortality shock since World War II. The LE losses in central, western, and northern Europe in 2020 and 2021 were drastic. Extrapolating the study findings from 2021, the researchers suggested that some countries may manage a smoother recovery to pre-pandemic trends due to pharmaceutical interventions and NPIs. Overall, it is still not fully understood how the COVID-19 pandemic altered the long-term LE trends globally.
Inequities in COVID-19 vaccination coverage for older adults highlighted in global study