ArticleInternational journal of epidemiology2023
Effectiveness and durability of a second COVID-19 booster against severe outcomes among older people in Norway: a population-based cohort study comparing mono- and bivalent booster doses.
Article in International journal of epidemiology, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 5 papers, 1 of them a synthesis 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
5 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Relative effectiveness of bivalent COVID-19 vaccine: a systematic review and meta-analysis.Frontiers in medicine · 2023Pooled it
- Protection from second booster vaccines and natural immunity against SARS-CoV-2 infections, 2022-2023.Epidemiology and infection · 2025Observational
- Long term bivalent mRNA vaccine effectiveness against COVID-19 hospitalisations and deaths in Portugal: a cohort study based on electronic health records.BMC infectious diseases · 2025Article
- Comparison of two methods for the estimation of COVID-19 vaccine effectiveness of the autumnal booster within the VEBIS-EHR network in 2022/23.Epidemiology and infection · 2025Article
- Relative effectiveness of bivalent boosters against severe COVID-19 outcomes among people aged ≥ 65 years in Finland, September 2022 to August 2023.Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin · 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
6 authors.
Funding
Abstract
backgroundEvidence on the durability of the protection of a fourth dose of a monovalent or bivalent messenger ribonucleic acid (mRNA) vaccine against coronavirus disease 2019 (COVID-19) among older people during the predominant Omicron period is needed.
methodsWe performed a population-based cohort study in Norway covering the time from 1 July 2022 to 15 January 2023, including individuals ≥75 years of age who had received at least a third dose. Using Cox proportional hazard models on severe COVID-19-associated outcome measures and all-cause mortality, we estimated the vaccine effectiveness of mono- and bivalent vaccines, comparing fourth- to third-dose recipients (>24 weeks ago). Vaccine status was included as a time-varying covariate and models were adjusted for potential confounders.
resultsWe included 408 073 individuals. A fourth dose with either monovalent or bivalent mRNA vaccine showed increased protection against COVID-19-associated mortality relative to a third dose in individuals ≥75 years of age. We estimated a protective effect for the bivalent BA.1 vaccine [adjusted hazard ratio (aHR) 0.08, 95% CI 0.02-0.32] relative to the bivalent BA.4-5 (aHR 0.27, 95% CI 0.14-0.56) and a monovalent dose (aHR 0.34, 95% CI 0.26-0.45) 2-9 weeks after vaccination compared with recipients with a third dose >24 weeks ago. The increased protective effect waned with no added protection for the monovalent vaccine after 33 weeks compared with a third dose.
conclusionsOur results indicate an increased protective effect of a fourth dose against severe outcomes compared with a third dose, with decreasing effect with time since the last dose.
Indexed as
Identifiers
What OpenQuestion holds
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.