How many lives have been saved by covid-19 vaccines?

For a look behind the scenes of our data journalism, sign up to Off the Charts, our weekly newsletter

Covid-19 vaccines began saving lives in clinical trials. But a new study, based in part on The Economist’s estimate of the pandemic’s true death toll, attempts to model just how many lives have been spared since vaccines became widely available to the public. (See chart.)

The study—published on June 23rd in Lancet Infectious Diseases—found that in the first year of vaccine rollout, jabs saved the lives of 19.1m-20.4m people. Without vaccines, the study estimates, roughly three times as many people would have died from covid in 2021 alone. And 6.8m-7.7m of the prevented deaths were in countries covered by COVAX, an initiative created to ensure vaccines were sent to poorer countries.

Still, a lack of vaccines in some parts of the world still led to avoidable deaths. Around 100 countries failed to reach the World Health Organisation’s goal of vaccinating 40% of their eligible populations by the end of 2021. The researchers estimate that this cost around 600,000 lives.

To arrive at these estimates the researchers, Oliver J. Watson, Gregory Barnsley and their colleagues at Imperial College London, began with an existing transmission model used to track the spread of covid infections. They then combined this model with The Economist’s estimate of the pandemic’s true death toll to estimate how deadly the pandemic would have been without vaccines.

The study has its limitations. It relies on assumptions about the share of estimated infections that led to death, for instance. China, which has limited reliable data, was excluded from the analysis, as were very small countries. That means the total number of actual averted deaths will be even higher. On the other hand, the researchers did not attempt to model how people or governments might have changed their behaviour to limit infections in the absence of vaccines. For all that, it is the most definitive answer yet to how many people owe their lives to the jabs. ■