Evidence map›Paper›PMID 42317109›Full record

ArticleEpidemiology and infection2026

Risk-of-bias assessment of vaccine effectiveness studies: a scoping review of systematic reviews.

Zahra Davoodi, Cassandra Laurie, Kylie Tingley, Becky Skidmore, Nicole Shaver, Maria E Sundaram, Deshayne B Fell, Melissa Brouwers, Giorgia Sulis

Abstract readScoping Review
In one paragraph

Article in Epidemiology and infection, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from 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.

2 · The registry

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.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

9 authors.

Zahra DavoodiSchool of Epidemiology and Public Health, https://ror.org/03c4mmv16University of Ottawa Faculty of Medicine, Canada.
Cassandra LaurieSchool of Epidemiology and Public Health, https://ror.org/03c4mmv16University of Ottawa Faculty of Medicine, Canada.
Kylie TingleyIndependent epidemiologist, Canada.
Becky SkidmoreIndependent information specialist, Canada.
Nicole ShaverSchool of Epidemiology and Public Health, https://ror.org/03c4mmv16University of Ottawa Faculty of Medicine, Canada.ORCID 0000-0003-3210-8895
Maria E Sundaramhttps://ror.org/025chrz76Marshfield Clinic Research Institute, USA.
Deshayne B FellSchool of Epidemiology and Public Health, https://ror.org/03c4mmv16University of Ottawa Faculty of Medicine, Canada.
Melissa BrouwersSchool of Epidemiology and Public Health, https://ror.org/03c4mmv16University of Ottawa Faculty of Medicine, Canada.
Giorgia SulisSchool of Epidemiology and Public Health, https://ror.org/03c4mmv16University of Ottawa Faculty of Medicine, Canada.ORCID 0000-0001-6641-0094

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Observational vaccine effectiveness (VE) studies provide essential real-world evidence but are prone to bias. Valid synthesis relies on rigorous risk-of-bias (RoB) assessment in systematic reviews of VE studies. Following JBI guidance, we mapped and described RoB assessment methodologies in systematic reviews of VE studies. We searched MEDLINE, Embase, and Web of Science from 1 January 2013 to 17 May 2023 and the grey literature from 1 January 2018 to 15 August 2023. Of 367 identified reviews, 38 lacked any RoB assessment, yielding 203 systematic reviews. Of these, 190 used existing tools (NOS (85/190, 44.7%), ROBINS-I (46/190, 24.2%), and JBI (11/190, 5.8%)) and 13 used an author-developed tool (13/203, 6.4%). Tools were adapted in 16.7% (34/203) of reviews and 7.2% (14/203) used multiple tools. Reviews included 20 (±25.7) observational studies, commonly cohorts (175/203, 86.2%), with COVID-19 (66/203, 32.5%) and seasonal influenza (62/203, 30.5%) frequently studied. VE was reported descriptively in 25.1% (51/203) of reviews, while 74.9% (152/203) provided meta-analyzed estimates primarily based on laboratory-confirmed infection (137/203, 67.5%) and symptomatic disease (130/203, 64.0%). Our findings indicate heterogeneous RoB assessment, reflected by use of different/multiple tools, frequent adaptations, author-developed methods, and absence of RoB assessment, highlighting the need for clearer guidance or tailored tools.

Indexed as

COVID-19 VaccinesVaccine EfficacyBiasCOVID-19HumansSystematic Reviews as TopicCOVID-19 Vaccinesevidence synthesis methodsmethodological assessmentobservational studiesquality appraisalstudy qualityvaccination

Identifiers

PMID42317109
PMCPMC13366358

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Registered trials

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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.