ArticleBMJ evidence-based medicine2022
Factors influencing estimated effectiveness of COVID-19 vaccines in non-randomised studies.
Article in BMJ evidence-based medicine, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 28 papers.
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
28 citing papers in PubMed.
- Considerations for assessing the feasibility of network meta-analysis of seasonal vaccines.Journal of comparative effectiveness research · 2026Article
- Interim 2025/26 influenza vaccine effectiveness estimates with immuno-epidemiological considerations for A(H3N2) subclade K protection, Canada, January 2026.Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin · 2026Article
- A narrative review of heterogeneity in SARS-CoV-2 infection outcomes and vaccine efficacy: strategizing pandemic preparedness in Africa.Frontiers in public health · 2026Review
- A Review of the Effects of Ipsilateral or Contralateral Vaccine Boosting on the Adaptive Immune Response.Vaccines · 2025Review
- The Mirror of Erised: a retrospective population-wide study of Czech all-cause mortality data by COVID-19 vaccination status.BMC public health · 2025Article
- Comparative analysis of humoral immunity kinetics following three COVID-19 vaccines in a multi-ethnic cohort of medical students and healthcare professionals across Malaysia.Scientific reports · 2025Observational
- Impact of unequal testing on vaccine effectiveness estimates across two study designs: a simulation study.Nature communications · 2025Article
- Article
- COVID-19 severity and vaccine effectiveness in Malawi: A test-negative case-control study.Journal of public health in Africa · 2025Article
- What Lessons can Be Learned From the Management of the COVID-19 Pandemic?International journal of public health · 2025Review
- Population-Based Influenza Vaccine Effectiveness Against Laboratory-Confirmed Influenza Infection in Southern China, 2023-2024 Season.Open forum infectious diseases · 2024Article
- Reports of Batch-Dependent Suspected Adverse Events of the BNT162b2 mRNA COVID-19 Vaccine: Comparison of Results from Denmark and Sweden.Medicina (Kaunas, Lithuania) · 2024Article
- Article
- COVID-19 Vaccine Effectiveness in Autumn and Winter 2022 to 2023 Among Older Europeans.JAMA network open · 2024Article
- A Critical Analysis of All-Cause Deaths during COVID-19 Vaccination in an Italian Province.Microorganisms · 2024Article
- Effectiveness of a fourth SARS-CoV-2 vaccine dose in previously infected individuals from Austria.European journal of clinical investigation · 2024Observational
- COVID-19 vaccine effectiveness against symptomatic infection with SARS-CoV-2 BA.1/BA.2 lineages among adults and adolescents in a multicentre primary care study, Europe, December 2021 to June 2022.Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin · 2024Article
- COVID-19 vaccine effectiveness against hospitalizations in Paraguay, May 2021-April 2022: A test-negative design.Vaccine · 2023Article
- The quality and pattern of rehabilitation interventions prescribed for post-COVID-19 infection patients: A systematic review andPreventive medicine reports · 2023Review
- Impact of study design on vaccine effectiveness estimates of 2 mRNA COVID-19 vaccine doses in patients with stage 5 chronic kidney disease.Kidney international · 2023Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
1 author.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Non-randomised studies assessing COVID-19 vaccine effectiveness need to consider multiple factors that may generate spurious estimates due to bias or genuinely modify effectiveness. These include pre-existing immunity, vaccination misclassification, exposure differences, testing, disease risk factor confounding, hospital admission decision, treatment use differences, and death attribution. It is useful to separate whether the impact of each factor admission decision, treatment use differences, and death attribution. Steps and measures to consider for improving vaccine effectiveness estimation include registration of studies and of analysis plans; sharing of raw data and code; background collection of reliable information; blinded assessment of outcomes, e.g. death causes; using maximal/best information in properly-matched studies, multivariable analyses, propensity analyses, and other models; performing randomised trials, whenever possible, for suitable questions, e.g. booster doses or comparative effectiveness of different vaccination strategies; living meta-analyses of vaccine effectiveness; better communication with both relative and absolute metrics of risk reduction and presentation of uncertainty; and avoidance of exaggeration in communicating results to the general public.
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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.