Observational studyEuropean journal of clinical investigation2024
Effectiveness of a fourth SARS-CoV-2 vaccine dose in previously infected individuals from Austria.
Observational study in European journal of clinical investigation, 2024. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 14 papers, 2 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
14 citing papers in PubMed, 2 syntheses or guidelines pooled it, 26 citations in OpenAlex.
- The importance of falsification endpoints in observational studies of vaccination to prevent severe disease: A critique of a harm-benefit analysis of BNT162b2 vaccination of 5- to 11-year-olds.Epidemiology and infection · 2024Pooled it
- Meta-analysis of hybrid immunity to mitigate the risk of Omicron variant reinfection.Frontiers in public health · 2024Pooled it
- Post-pandemic mortality patterns and COVID-19 burden considering multiple death causes.European journal of epidemiology · 2026Article
- The structure and function of membrane protein in coronavirus infection and its applications in the development of vaccines and therapeutic drugs.Frontiers in microbiology · 2026Review
- Nationwide estimates of SARS-CoV-2 infection fatality rates and numbers needed to vaccinate for COVID-19 vaccines in 2024 in Austria.European journal of clinical investigation · 2026Article
- Association of SARS-CoV-2 vaccination status with risk of influenza-like illness and loss of workdays in healthcare workers.Communications medicine · 2025Article
- Estimates of SARS-CoV-2 Infections and Population Immunity After the COVID-19 Pandemic in Austria: Analysis of National Wastewater Data.The Journal of infectious diseases · 2025Article
- Lessons to Be Learned From the COVID-19 Pandemic: Some Further Ideas.International journal of public health · 2025Article
- Innovative approaches for vaccine trials as a key component of pandemic preparedness - a white paper.Infection · 2024Review
- Long-term effectiveness of an ultra-rapid rollout vaccination campaign with BNT162b2 on the incidence of SARS-CoV-2 infection.iScience · 2024Article
- Effectiveness of the First and Second Severe Acute Respiratory Syndrome Coronavirus 2 Vaccine Dose: A Nationwide Cohort Study From Austria on Hybrid Versus Natural Immunity.Open forum infectious diseases · 2024Article
- Co-Mutations and Possible Variation Tendency of the Spike RBD and Membrane Protein in SARS-CoV-2 by Machine Learning.International journal of molecular sciences · 2024Article
- Effectiveness of a fourth SARS-CoV-2 vaccine dose in previously infected individuals from Austria.European journal of clinical investigation · 2024Observational
- All-cause mortality according to COVID-19 vaccination status: An analysis of the UK office for National statistics public data.F1000Research · 2024Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
11 authors at 5 institutions in 4 countries.
Funding
Abstract
introductionEvidence is limited on the effectiveness of a fourth vaccine dose against coronavirus disease 2019 (COVID-19) in populations with prior severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. We estimated the risk of COVID-19 deaths and SARS-CoV-2 infections according to vaccination status in previously infected individuals in Austria.
methodsThis is a nationwide retrospective observational study. We calculated age and gender adjusted Cox proportional hazard ratios (HRs) of COVID-19 deaths (primary outcome) and SARS-CoV-2 infections (secondary outcome) from 1 November to 31 December 2022, primarily comparing individuals with four versus three vaccine doses. Relative vaccine effectiveness (rVE) was calculated as (1-HR) X 100.
resultsAmong 3,986,312 previously infected individuals, 281,291 (7,1%) had four and 1,545,242 (38.8%) had three vaccinations at baseline. We recorded 69 COVID-19 deaths and 89,056 SARS-CoV-2 infections. rVE for four versus three vaccine doses was -24% (95% CI: -120 to 30) against COVID-19 deaths, and 17% (95% CI: 14-19) against SARS-CoV-2 infections. This latter effect rapidly diminished over time and infection risk with four vaccinations was higher compared to less vaccinated individuals during extended follow-up until June 2023. Adjusted HR (95% CI) for all-cause mortality for four versus three vaccinations was 0.79 (0.74-0.85). DISCUSSION: In previously infected individuals, a fourth vaccination was not associated with COVID-19 death risk, but with transiently reduced risk of SARS-CoV-2 infections and reversal of this effect in longer follow-up. All-cause mortality data suggest healthy vaccinee bias.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.