An "additional" 267,000 babies are thought to have died in low- and middle-income countries in 2020 due to the economic impact of the COVID-19 pandemic.
While the infection disproportionately affects older people, economic downturns – a result of stunted tourism and reduced spending amid the world's various lockdowns – can impact the health of anyone, regardless of their age.
To better understand COVID's impact, economists from World Bank compared the gross domestic product (GDP) – the total value of a nation's annual goods and services – of 83 countries between 1985 and 2018, linking the data to the nations' birth rates.
Economic growth projections for 2019 and 2020 were then estimated to gauge the effect of the latter year's downturn in 128 nations.
Results, published in the BMJ Open, suggest an additional 267,208 babies under one years old died in 2020 – a 6.8% increase on what would have been expected.
"Regardless of the exact number of projected deaths, the large number of excess infant deaths estimated in our analysis underscores the vulnerability of this age group to negative aggregate income shocks [a sudden and significant decline in earnings], such as those induced by the COVID-19 pandemic," wrote the economists.
"Several mechanisms are likely driving this increase in mortality among children 0–1 year of age – impoverishment at the household level will lead to worse nutrition and care practices for infants and reduced ability to access health services, while the economic crisis might also affect the supply and quality of services offered by the health systems."
The global economy is expected to have shrunk by almost 5% in 2020, increasing the number of people living in poverty by 120 million.
In low- and middle-income countries, economic crises are known to particularly increase deaths among vulnerable groups, like babies.
Previous studies that estimated the pandemic's effect on indirect deaths, not those caused by the coronavirus itself, focused on assumed disruptions to essential health services.
The World Bank economists instead analysed the aggregated income shock in low- and middle-income countries, according to a projected decline in GDP on children younger than one-year-old.
Data on the GDP per head of the population were linked to 5.2 million births, as reported in Demographic and Health Surveys between 1985 and 2018. More than four in five (82%) of these births occurred in low- and lower middle-income countries.
Finally, the team applied International Monetary Fund economic growth projections for 2019 and 2020 to predict the effect of the economic downturn in the latter year on infant deaths.
South Asia was found to have the highest number of "excess" infant deaths, totalling 113,141 across eight countries.
Of these fatalities, 99,642 were expected to have occurred in India. More than 24 million babies are born every year in India, whose economy is expected to have shrunk by 17.3% in 2020.
In Africa, 82,239 additional baby deaths are thought to have been the result of the pandemic. This is compared to the 28,000 to 50,000 extra infant deaths after the 2009 financial crisis.
The economists have stressed their study has several limitations, with calculations being based on past data and the team only considering the short-term impact of GDP fluctuations on baby death rates.
Economic growth projections that occurred between October 2019 and October 2020 were also assumed to be the result of the pandemic alone, despite some of the countries experiencing natural disasters and political crises that also affected their national income.
Nevertheless, the economists added: "As countries, health system, and the wider global community continue efforts to prevent and treat COVID-19, we should also consider resources to stabilise health systems and strengthen social safety nets in order to mitigate the human, social and economic consequences of the pandemic and related lockdown policies."
Watch: Do coronavirus vaccines affect fertility?