New Delhi: The novel coronavirus could end up impacting life expectancies by anywhere between one and nine years in various parts of the world, a study on the long-term population-level impact of the virus has found.
The study by researchers from at least three countries has found that the effect will vary depending on the current life expectancies in each country.
Published in PLOS One journal, the analysis has also linked the Covid-19 prevalence rate — the proportion of a population that has a disease — to life expectancy.
“At a 10 per cent Covid-19 prevalence rate, the loss in life expectancy at birth is likely above 1 year in North America and Europe and in Latin America and the Caribbean,” according to researchers from Shanghai University, the International Institute for Applied Systems Analysis in Austria, and the University of East Anglia in the United Kingdom. “In Southeastern Asia and sub-Saharan Africa, one year lost in life expectancy corresponds to an infection prevalence of about 15 per cent and 25 per cent, respectively.”
Using this metric, the researchers have calculated the loss in life expectancy for higher prevalence rates.
“Given the uncertainty in fatality rates, with a 50 per cent prevalence of Covid-19 infections under 95 per cent prediction intervals, life expectancy would drop by 3 to 9 years in North America and Europe, by 3 to 8 years in Latin America and the Caribbean, by 2 to 7 years in Southeastern Asia, and by 1 to 4 years in sub-Saharan Africa,” the analysis states. “In all prevalence scenarios, as long as the Covid-19 infection prevalence rate remains below 1 or 2 per cent, Covid-19 would not affect life expectancy in a substantial manner.”
Previous epidemics such as the 1918 influenza pandemic and the 2014 Ebola virus outbreak resulted in a drop in life expectancy at birth of 11.8 years and 1.6–5.6 years in the US and Liberia, respectively.
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‘Could wipe out gains made over years’
The study says the Covid-19 pandemic could wipe out gains that countries have made in life expectancy over many decades with health system strengthening, vaccines, ensuring equity in healthcare delivery, and many such measures.
“It took Europe almost 20 years for average life expectancy at birth to increase by six years — from 72.8 years in 1990 to 78.6 years in 2019. Covid-19 could thus set back this indicator in 2020 to the values observed some time ago,” IIASA researcher Sergei Scherbov, who worked on the study, said. “However, we do not know what is going to happen further. In many countries fatality from Covid is strongly decreasing, probably because the protocol of Covid treatment became better defined.”
Life expectancy is calculated based on annual mortality rates. The high number of deaths in Covid, especially in older people could end up skewing that number. While higher incidence of the disease is not directly linked to mortality, overcrowding of health facilities could cause more casualties, the researchers reasoned. That is why higher incidence would have a larger impact.
“The impact of Covid-19 on the period life-expectancy would be lower in Southeastern Asia, and even much lower in sub-Saharan Africa,” the study states.
“For Southeastern Asia, one year lost in life expectancy corresponds to an infection prevalence of about 15 per cent compared to a prevalence of 25 per cent in sub-Saharan Africa,” it adds. “At 50 per cent infection prevalence, the years of life lost amount to 3.5 years in South Eastern Asia and 2 years in sub-Saharan Africa. In short, loss in life expectancy in sub-Saharan Africa would be half of those in North America and Europe, while years of life lost due to Covid-19 in Southeastern Asia would lie between the other two regions.”
According to the study, there will be no impact on life expectancy if the incidence level is low. In regions with high life expectancy (80s), the trend of that number rising would be broken only at a threshold incidence of two per cent, the study states.
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