ArticleVaccines2025
COVID-19 Vaccine Effectiveness Against Mortality in the Omicron Period: Evidence from Linked Mortality and Vaccination Records.
Article in Vaccines, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.
What it found
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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
1 citing paper in PubMed.
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Corrections and comments
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Authors and funding
11 authors.
Funding
Abstract
objectiveThis study aimed to assess COVID-19 vaccine effectiveness against death (VE), controlling for healthy vaccinee bias.
methodsWe link all adult deaths through year-end 2022 in the State of Indiana, U.S.A., to vaccination records and identify which deceased received primary vaccination (measured as either one or two initial doses) and which received one or two booster doses. We measure COVID-19 mortality with the COVID Excess Mortality Percentage (CEMP). CEMP is calculated, for a group defined by various characteristics (age, sex, time period), as COVID-19 deaths divided by non-COVID natural deaths. The CEMP outcome measure accounts for healthy vaccinee bias by using non-COVID natural mortality to control for differences in population health.
resultsWe find a large healthy vaccinee bias. Controlling for this bias, we find substantial VE for primary vaccination and the first booster dose during the first five vaccine-available calendar quarters, from 1Q2021 through 1Q2022 (end of Omicron infection wave). However, over 2Q-4Q2022, we find no evidence for primary-vaccination VE, and find moderate but statistically insignificant booster VE, which largely wanes by 4Q2022.
conclusionsIt is known that by 2Q2022, most people had natural immunity from prior COVID-19 infection. Thus, our results for 2Q-4Q2022 largely reflect comparing hybrid (infection plus vaccination) immunity to infection-only immunity. In this period, we find negligible mortality benefit from primary vaccination, and moderate but waning benefit from a booster dose. POLICY IMPLICATIONS: Controlling for healthy vaccinee bias is crucial when estimating VE. We found limited VE against COVID-19 mortality over 2Q-4Q2022, but lacked data for more recent periods.
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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.