COVID-19 vaccines prevented almost 20 million deaths worldwide in the first year of the vaccine programme, according to a modelling study published in The Lancet on Friday.

The first modelling study to quantify the global impact of COVID-19 vaccines estimates that 19.8 million out of a potential 31.4 million deaths were prevented in the first year after vaccines were introduced between 8 December 2020 and 8 December 2021.

“High and upper-middle income countries accounted for the greatest number of prevented deaths (12.2 million/ 19.8 million), highlighting inequalities in access to vaccines around the world,” according to The Lancet.

A further 599,300 deaths could have been averted if the World Health Organisation’s target of vaccinating 40% of the population in every country by the end of 2021 had been met.

The study is based on data from 185 countries, using COVID-19 death records and total excess deaths from each country, or estimates where official data was not available. 

To account for under-reporting of deaths in countries with weaker surveillance systems, they carried out a separate analysis based on the number of excess deaths recorded above those expected during the same time period. 

Where official data was not available, the team used estimates of all-cause excess mortality. These analyses were compared with an alternative hypothetical scenario in which no vaccines were delivered.

New Research: Global impact of the first year of COVID-19 vaccination: a mathematical modelling study https://t.co/VIpZMnZ3mY (1/2)

— The Lancet Infectious Diseases (@TheLancetInfDis) June 24, 2022

COVAX saved 7.5 million lives

“Our findings offer the most complete assessment to date of the remarkable global impact that vaccination has had on the COVID-19 pandemic. Of the almost 20 million deaths estimated to have been prevented in the first year after vaccines were introduced, almost 7.5 million deaths were prevented in countries covered by the COVID-19 Vaccine Access initiative (COVAX),” said Dr Oliver Watson, lead author of the study, from Imperial College London.

“Our findings show that millions of lives have likely been saved by making vaccines available to people everywhere, regardless of their wealth. However, more could have been done. If the targets set out by the WHO had been achieved, we estimate that roughly one in five of the estimated lives lost due to COVID-19 in low-income countries could have been prevented.”

COVAX has facilitated access to affordable vaccines for lower-income countries to try to reduce inequalities, with an initial target of giving two vaccine doses to 20% of the population in countries covered by the commitment by the end of 2021. 

The World Health Organization (WHO) expanded this target by setting a global strategy to fully vaccinate 70% of the world’s population by mid-2022, with an interim target of vaccinating 40% of the population of all countries by the end of 2021.

Despite the speed of the vaccine roll-out worldwide, more than 3.5 million COVID-19 deaths have been reported since the first vaccine was administered in December 2020.

“Quantifying the impact that vaccination has made globally is challenging because access to vaccines varies between countries, as does our understanding of which COVID-19 variants have been circulating, with very limited genetic sequence data available for many countries,” said Gregory Barnsley, co-first author of the study, from Imperial College London. 

“It is also not possible to directly measure how many deaths would have occurred without vaccinations. Mathematical modelling offers a useful tool for assessing alternative scenarios, which we can’t directly observe in real life.”

Image Credits: International Monetary Fund/Ernesto Benavides.