ArticleResearch square2026
Effectiveness of maternal COVID-19 vaccination varies by gestational timing: results from a claims-based cohort study, 2020-2022.
Article in Research square, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
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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
0 citing papers in PubMed.
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Authors and funding
7 authors.
Funding
Abstract
We evaluated COVID-19 vaccine effectiveness (VE) during pregnancy by dose and trimester in a claims-based cohort of 414,909 pregnant women from 25 December 2020 to 16 September 2022. Vaccination was modeled as a time-varying exposure using weighted Cox proportional hazards models to estimate VE against medically-attended COVID-19 and COVID-19-related hospitalization. Overall, 58,975 (14.2%) women received ≥ 1 dose during pregnancy. We identified 39,202 COVID-19 cases, including 1,130 hospitalizations, with most outcomes (> 93%) occurring during unvaccinated person-time. VE against medically-attended COVID-19 was low-to-moderate across trimesters, with the highest estimates after late second trimester vaccination (36.3%, 95% CI: 26.9-44.4) or ≥ 2 doses (40.7%, 95% CI: 26.3-52.3). VE against hospitalization was higher, albeit with wider confidence intervals (late second trimester, 73.1%, 95% CI: 13.3-91.6). COVID-19 vaccination during pregnancy provided meaningful maternal protection, particularly against severe disease, with some indications that protection may be greatest when given during later gestational periods.
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