# Nationwide estimates of SARS‐CoV‐2 infection fatality rates and numbers needed to vaccinate for COVID‐19 vaccines in 2024 in Austria

## TL;DR

In 2024, Austria's low SARS-CoV-2 infection fatality rate meant high numbers of people needed to be vaccinated to prevent one death or save a life-year, especially for younger age groups.

## Contribution

This study provides updated nationwide estimates of NNV and LYS for SARS-CoV-2 vaccination in Austria in 2024, stratified by age and residency.

## Key findings

- The 2024 IFR in Austria was 0.048%, with NNV to prevent one death being over 4,000 for most age groups.
- For individuals aged 85+, NNV was lower but still not favorable, with LYS under 2,000 only under favorable assumptions.
- Sensitivity analyses showed limited benefit of vaccination for most age groups beyond the oldest cohorts.

## Abstract

Post‐pandemic years are characterized by widespread previous population immunization against COVID‐19. Whether and for whom COVID‐19 vaccinations are still justified is unclear. We use nationwide estimates of IFR and literature‐derived estimates of vaccine effectiveness (VE) to calculate numbers needed to vaccinate to prevent one COVID‐19 death (NNV) and for one life‐year saved (LYS) in Austria in 2024.

In this retrospective analysis, we calculate SARS‐CoV‐2 IFR during 2024 in Austria according to previously published wastewater‐based infection estimates and available mortality data. Using literature‐derived VE estimates, we calculate NNV to prevent one COVID‐19 death and for one LYS in strata according to age groups, nursing home residency and vaccination in 2024. We repeat analyses with sensitivity range values of parameters.

In 2024, total IFR was .048%. NNV (LYS) in the age groups 0–19, 20–39, 40–59, 60–74 and 75–84 years was very high: i.e. 5,497,526 (151,570), 2,432,498 (92,614), 415,714 (24,777), 35,925 (3748) and 4882 (1009), respectively, in community dwellers. In the 85+ years age group, IFRs of unvaccinated/vaccinated were .91%/.77% for community dwellers and 1.22%/1.04% for nursing home residents. The 85+ year age group had NNV estimates of 1215 and 907 (LYS: 525 and 1896) in community dwellers and nursing home residents, respectively. Sensitivity analyses yielded LYS < 1000 only under some favourable assumptions in the 75–84 and 85+ years old age strata.

In 2024 in Austria, SARS‐CoV‐2 IFR was low and NNV and LYS of COVID‐19 vaccinations correspondingly non‐favorably high, even for very old individuals.

In 2024, Austria's infection fatality rate (IFR) for SARS‐CoV‐2 was .048%, indicating a low COVID‐19 mortality risk. Using literature‐based vaccine effectiveness estimates, numbers needed to vaccinate (NNV) to prevent one death and one life‐year saved (LYS) were extremely high across all age groups, except among the very old. For individuals aged 85+, NNV remained relatively lower but still non‐favourable. Sensitivity analyses confirmed that meaningful benefit was limited to selected assumptions, suggesting little justification for widespread COVID‐19 vaccination beyond the oldest cohorts.