COVID-19: years of life lost (YLL) and saved (YLS) as an expression of the role of vaccination

Abstract

When evaluating vaccine efficacy, the conventional measures include reduction of risk of hospitalization and death. The number of patients dying with or without vaccination is often in the public spotlight. However, when evaluating public health interventions or the burden of disease, it is more illustrative to use mortality metrics taking into account also prematurity of the deaths, such as years of life lost (YLL) or years of life saved (YLS) thanks to the vaccination. We develop this approach for evaluation of the difference in YLL and YLS between COVID-19 victims with or without completed vaccination in the autumn pandemic wave (2021, October–December) in Czechia. For the analysis, individual data about all COVID-19 deaths in the country (N = 5797, during the studied period) was used. While 40.6% of the deaths are in cohorts with completed vaccination, this corresponds to 35.1% of years of life lost. The role of vaccination is expressed using YLS and hypothetical numbers of deaths. The registered number of deaths is approximately 3.5 times lower than it would be expected without vaccination. The results illustrate that vaccination is more effective in saving lives than suggested by simplistic comparisons.

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“…The present work shows the great importance of vaccination not only to prevent hospitalization of infected people, but also to reduce deaths in agreement with published evidences (Machado et al 2022, Hulíková Tesárková and Dzúrová 2022, Rachaniotis et al 2022: the maximum number of deaths and years of life lost occurs during the period without mandatory vaccination.…”

Using Potential Years of Life Lost (PYLL) to Compare Premature Mortality between Romanian Counties to Confirmed COVID-19 Cases in 2020 and 2021

“…In Portugal, COVID-19 accounted for 4.2% of all years of life lost, with an exceedance of 35,510 Years of Life Lost (YLL or PYLL); of this, 72% was caused by COVID-19 and 28% by non-COVID-19 causes [ 36 ]. According to a study from Czechia (2022), complete vaccination reduced the number of potential life years lost to death by approximately 3.5 times compared to the number of expected deaths between October and December 2021 [ 37 ]. A study conducted in 34 countries found that COVID-19 caused 9 to 21 years of life lost per deceased patient, with East Asia and Oceania having fewer YLL per capita than North America and Europe [ 38 ].…”

ACE2-Decorated Virus-Like Particles Effectively Block SARS-CoV-2 Infection

“… 24 As of March 30, 2023, there were 382 candidate vaccines, 183 of which have been in clinical trials, and as of June 6, 2023, Pfizer-BioNTech, Moderna, and Novavax COVID-19 vaccines were authorized for emergency use and/or FDA-approved. 25 , 26 Despite the availability of effective COVID-19 vaccine saving thousands of lives, 27 the ability of fast adaptation of SARS-CoV-2 through acquiring new mutations can dampen the effectivity of these vaccines over time. This warrants the development of better direct acting SARS-CoV-2 antivirals.…”