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Data shows vaccines have saved over 2.5 million lives worldwide during the COVID-19 pandemic
Last reviewed: 27.07.2025
Vaccination against SARS-CoV-2 prevented 2.533 million deaths globally between 2020 and 2024; one death was prevented for every 5,400 vaccine doses administered.
About 82% of the lives saved by vaccines involved people vaccinated before exposure to the virus, 57% during the omicron period, and 90% in people aged 60 years and older. In total, vaccines saved 14.8 million life years (one life year saved for every 900 doses of vaccine).
These are some of the data published in an unprecedented study published in the journal Jama Health Forum and coordinated by Professor Stefania Boccia, Professor of General and Applied Hygiene at the Catholic University, with the participation of Dr. Angelo Maria Pezzullo, researcher in General and Applied Hygiene, and Dr. Antonio Cristiano, resident in Hygiene and Preventive Medicine.
The two researchers spent time at Stanford University collaborating directly with the group of Professor John P. A. Ioannidis, Director of the Meta-Research Innovation Centre (METRICS), as part of the project ‘European network staff eXchange for integrating precision health in the health care sysTem – ExACT’.
Professor Boccia and Dr Pezzullo explain: “Before our study, there have been several studies that have tried to estimate the number of lives saved by vaccines using different models and at different times or in specific parts of the world, but this is the most comprehensive because it is based on global data, covers the omicron period, calculates the number of life years saved and relies on fewer assumptions about the course of the pandemic.”
Experts looked at population data from around the world, using a range of statistical methods to determine which COVID cases occurred before or after vaccination, before or after the omicron period, and how many of them died (and at what age).
“We compared these data with estimates modeled in the absence of COVID vaccination and were then able to calculate the number of people saved by COVID vaccines and the number of life years gained because of them,” explains Dr. Pezzullo.
It also found that the majority of life years saved (76%) were in people over 60 years of age, but those living in long-term care facilities accounted for only 2% of the total. Children and adolescents (0.01% of lives saved and 0.1% of life years saved) and young adults aged 20–29 (0.07% of lives saved and 0.3% of life years saved) contributed very little to the overall effect.
Professor Boccia concludes: “These estimates are significantly more conservative than previous calculations, which focused mainly on the first year of vaccination, but clearly demonstrate an important overall benefit from COVID-19 vaccination over the period 2020–2024.
Most of the benefits, in terms of lives and life years saved, have been delivered to the part of the global population that is typically more vulnerable – older people.”