By Michael Le Page

Copyright newscientist

The covid-19 vaccines cost $79 billion to develop and deliver globally, but provided health and economic benefits worth between $5 trillion and $38 trillion globally in the first year alone, based on avoided infections, hospitalisations and deaths. That is a return on investment of between $60 and $475 per dollar invested.

“These studies show the benefits that vaccines have, not just in terms of saving lives, but also that there is a strong economic argument,” says Oliver Watson at Imperial College London. “Hopefully, this will highlight the value of continued investment in vaccine research and development.”

Watson and his colleagues didn’t attempt to estimate how much higher global economic growth was as a result of the vaccines than it would have been otherwise. Rather, their work is an estimate of the economic values of the health benefits, based on their previous 2022 study that estimated that covid-19 vaccines averted more than 14 million deaths in their first year of use.

For avoided infections, the team estimated how many days of work lost to illness were averted and the productivity value of those work days. For avoided hospitalisations, the team estimated the costs of the healthcare that wasn’t required.

For deaths, the team estimated how many years of life were saved and the value of those years based on a measure of either how much society values years of life or how much people are willing to pay for an extra year of life – a standard approach used in many other studies.

The lower estimate of $5 trillion in benefits came from the approach based on how much society values lives, and the $38 trillion figure is based on how much individuals value their lives.

Looking at years of life saved means the estimate takes into account the fact that many of those whose lives were saved by vaccines weren’t likely to live much longer, says Watson. Some other approaches put a value on lives saved regardless of age, which would result in a much higher estimation of the economic benefits.

“This study highlights the tremendous magnitude of benefits and returns on investment that covid vaccines brought nations throughout the globe,” says Richard Carpiano at the University of California, Riverside. “Studies like this are important because resources are finite and policy-makers have to make important decisions about how to allocate resources.”

“It shows that covid vaccination gave an excellent return on investment,” says Angela Rasmussen at the University of Saskatchewan in Canada.

The analysis is timely given recent events, such as the decision by the US to discontinue half a billion dollars in funding for mRNA vaccine development, says Carpiano. Watson says the timing is a coincidence, as his team had been working on the estimates since before the last US election.

Watson’s 2022 study estimating that vaccines saved more than 14 million lives in 2021 alone has come under fire from vaccine sceptics. A common claim is that it cannot be right because the number of excess deaths – that is, deaths likely to be due to covid-19 – was even higher in 2021 than in 2020.

But 2021 was the year that many measures for controlling the spread of covid-19, such as lockdowns, were lifted, meaning many more people were exposed to the virus than in 2020, says Watson. Without vaccination, death rates would have been much higher. “Those kind of arguments struggle to understand that counterfactual,” he says.

A study published in July this year estimated that covid-19 vaccines saved 2.5 million lives globally up to the end of 2024 – far less than the estimate from Watson’s team. That is because the July study uses much lower figures for what proportion of people infected with covid-19 died, how many got vaccinated, how effective the vaccines were at preventing deaths and so on.

Watson thinks the numbers in his study are more accurate. Rasmussen also thinks the July study underestimates the number of lives saved. “But even if [the July] estimates are closer to the mark, more than 2 million lives saved is still very successful,” she says.

Almost all other estimates of the number of lives saved by covid-19 vaccines are region-specific. For instance, a World Health Organization study estimated that covid-19 vaccines had saved 1.4 million lives in Europe alone by March 2023. “[This] broadly showed similar estimates to ours when we looked at the numbers for Europe,” says Watson.