Estimated number of lives directly saved by COVID-19 vaccination programmes in the WHO European Region from December, 2020, to March, 2023: a retrospective surveillance study

Background: By March, 2023, 54 countries, areas, and territories (hereafter CAT) in the WHO European Region had reported more than 2·2 million COVID-19-related deaths to the WHO Regional Office for Europe. Here, we estimated how many lives were directly saved by vaccinating adults in the WHO European Region from December, 2020, to March, 2023. Methods: In this retrospective surveillance study, we estimated the number of lives directly saved by age group, vaccine dose, and circulating variant-of-concern (VOC) period, regionally and nationally, using weekly data on COVID-19 mortality and infection, COVID-19 vaccination uptake, and SARS-CoV-2 virus characterisations by lineage downloaded from The European Surveillance System on June 11, 2023, as well as vaccine effectiveness data from the literature. We included data for six age groups (25-49 years, 50-59 years, ≥60 years, 60-69 years, 70-79 years, and ≥80 years). To be included in the analysis, CAT needed to have reported both COVID-19 vaccination and mortality data for at least one of the four older age groups. Only CAT that reported weekly data for both COVID-19 vaccination and mortality by age group for 90% of study weeks or more in the full study period were included. We calculated the percentage reduction in the number of expected and reported deaths. Findings: Between December, 2020, and March, 2023, in 34 of 54 CAT included in the analysis, COVID-19 vaccines reduced deaths by 59% overall (CAT range 17-82%), representing approximately 1·6 million lives saved (range 1·5-1·7 million) in those aged 25 years or older: 96% of lives saved were aged 60 years or older and 52% were aged 80 years or older; first boosters saved 51% of lives, and 60% were saved during the Omicron period. Interpretation: Over nearly 2·5 years, most lives saved by COVID-19 vaccination were in older adults by first booster dose and during the Omicron period, reinforcing the importance of up-to-date vaccination among the most at-risk individuals. Further modelling work should evaluate indirect effects of vaccination and public health and social measures.

Research in context: - Evidence before this study: Since it was first identified in late December, 2019, COVID-19 has caused disproportionately high mortality rates in older adults (aged ≥60 years). With the rapid development, licensing, and availability of novel COVID-19 vaccines, immunisation campaigns across the WHO European Region started in late 2020 and March, 2021, initially targeting the most vulnerable and exposed populations, including older adults, people with comorbidities, and health-care professionals. We searched PubMed, without language restrictions, for articles published between Dec 1, 2020, and July 31, 2024, using the search terms “(impact COVID-19 vaccin*)” NOT “(cancer)” NOT “(tb)” NOT “(tuberculosis)” NOT “(childhood immunization)” NOT “(liver)” NOT “(diabetes)” NOT “(ebola)”. 82 identified studies have estimated the number of lives saved by COVID-19 vaccination, both at national level (n=71) and multi-country level (n=11), in the earlier stages of the COVID-19 pandemic. However, only one country-level study assessed the number of lives saved beyond January, 2022, when the Omicron variant of concern (VOC) circulated, a period when vaccination coverage was high in many countries, areas, and territories (CAT), but SARS-CoV-2 transmission was at its highest. - Added value of this study: To our knowledge, this is the first retrospective surveillance study to quantify the impact of COVID-19 vaccination in adults, according to age group and variant, for the entire pandemic period across multiple countries. We calculated the numbers of lives saved by age group, vaccine dose, and period of circulation of VOC, across diverse settings, using real-world data reported for 34 CAT in the WHO European Region between December, 2020, to April, 2023. For this period, we estimated that COVID-19 vaccination programmes were associated with an overall 59% reduction (CAT range 17–82%) in the number of deaths among people aged 25 years or older, representing over 1·6 million lives saved (range 1·5–1·7 million). The first booster saved the most lives (51% of all lives saved). Those aged 60 years or older accounted for 96% of the total lives saved whereas people aged 80 years or older represented 52% of the total lives saved, and 60% of all lives were saved during the Omicron period. - Implications of all the available evidence: Our results reinforce the importance of up-to-date COVID-19 vaccination, particularly among older age groups. Communication campaigns supporting COVID-19 vaccination should stress the value of COVID-19 vaccination in saving lives to ensure that vulnerable groups are up to date with vaccination ahead of periods of potential increased transmission.