Covid-19 vaccines (疫苗) 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 (伤亡人数), attempts to model just how many lives have been spared since vaccines became widely available to the public.
The study— published on June 23rd in Lancet Infectious Diseases— found that in the first year of vaccines that were invented and introduced to the public , jabs (注射疫苗) saved the lives of people between 19.1 million and 20.4 million. Without vaccines, the study estimates, roughly three times as many people would have died from Covid-19 in 2021 alone. And 6.8 million — 7.7millon of the prevented deaths were in countries covered by COVAX ( Covid-19 Vaccines Global Access), 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 Organization's (WHO) goal of vaccinating 40% of their qualified 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-19 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.
As for the study, every coin has two sides. It relies on assumptions about the share of estimated infections that led to death, for instance. Some small countries, which have limited reliable data, were not included in the analysis. That means the total number of actual avoided deaths will be even higher. On the other hand, the researchers did not attempt to model how people or governments might have changed their behavior 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.