ReviewEpidemiology (Cambridge, Mass.)2021
Theoretical Framework for Retrospective Studies of the Effectiveness of SARS-CoV-2 Vaccines.
Review in Epidemiology (Cambridge, Mass.), 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 73 papers, 3 of them syntheses 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
73 citing papers in PubMed, 3 syntheses or guidelines pooled it.
- The efficacy and effectiveness of COVID-19 vaccines in Iran: a systematic review and meta-analysis.BMC infectious diseases · 2025Pooled it
- Prior infections and effectiveness of SARS-CoV-2 vaccine in test-negative studies: a systematic review and meta-analysis.American journal of epidemiology · 2024Pooled it
- The effectiveness of COVID-19 vaccines in reducing the incidence, hospitalization, and mortality from COVID-19: A systematic review and meta-analysis.Frontiers in public health · 2022Pooled it
- Article
- Extensive cryptic circulation sustains mpox among men who have sex with men.Nature communications · 2026Article
- Proposed study design for estimating COVID-19 vaccine effectiveness in post-pandemic Taiwan.Journal of the Chinese Medical Association : JCMA · 2026Article
- Article
- Protection from second booster vaccines and natural immunity against SARS-CoV-2 infections, 2022-2023.Epidemiology and infection · 2025Observational
- SARS-CoV-2 mRNA Vaccine Effectiveness in the Borriana COVID-19 Cohort: A Prospective Population-Based Cohort Study.Epidemiologia (Basel, Switzerland) · 2025Article
- Improved Methods for Vaccine Effectiveness Studies.The Journal of infectious diseases · 2025Article
- Article
- Impact of unequal testing on vaccine effectiveness estimates across two study designs: a simulation study.Nature communications · 2025Article
- Intensity of public health and social measures are associated with effectiveness of SARS-CoV-2 vaccine in test-negative study.medRxiv : the preprint server for health sciences · 2025Article
- Evaluating the Test-Negative Design for COVID-19 Vaccine Effectiveness Using Randomized Trial Data: A Secondary Cross-Protocol Analysis of 5 Randomized Clinical Trials.JAMA network open · 2025Article
- Tracking vaccine effectiveness in an evolving pandemic, countering misleading hot takes and epidemiologic fallacies.American journal of epidemiology · 2025Article
- A Double Machine Learning Approach for the Evaluation of COVID-19 Vaccine Effectiveness Under the Test-Negative Design: Analysis of Québec Administrative Data.Statistics in medicine · 2025Article
- Strength and durability of indirect protection against SARS-CoV-2 infection through vaccine and infection-acquired immunity.Nature communications · 2025Article
- Case-only analysis of routine surveillance data: detection of increased vaccine breakthrough infections with SARS-CoV-2 variants in Europe.Epidemiology and infection · 2025Article
- Repercussion of SARS-CoV-2 on the Sexual Function in Males: An Updated Review.Infectious disorders drug targets · 2025Review
- Severity-dependent test-seeking behaviors and test-negative designs: impact on estimated vaccine effectiveness and utility of analytic and design choices.American journal of epidemiology · 2024Article
13 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
9 authors.
Funding
Abstract
Observational studies of the effectiveness of vaccines to prevent COVID-19 are needed to inform real-world use. Such studies are now underway amid the ongoing rollout of SARS-CoV-2 vaccines globally. Although traditional case-control and test-negative design studies feature prominently among strategies used to assess vaccine effectiveness, such studies may encounter important threats to validity. Here, we review the theoretical basis for estimation of vaccine direct effects under traditional case-control and test-negative design frameworks, addressing specific natural history parameters of SARS-CoV-2 infection and COVID-19 relevant to these designs. Bias may be introduced by misclassification of cases and controls, particularly when clinical case criteria include common, nonspecific indicators of COVID-19. When using diagnostic assays with high analytical sensitivity for SARS-CoV-2 detection, individuals testing positive may be counted as cases even if their symptoms are due to other causes. The traditional case-control design may be particularly prone to confounding due to associations of vaccination with healthcare-seeking behavior or risk of infection. The test-negative design reduces but may not eliminate this confounding, for instance, if individuals who receive vaccination seek care or testing for less-severe illness. These circumstances indicate the two study designs cannot be applied naively to datasets gathered through public health surveillance or administrative sources. We suggest practical strategies to reduce bias in vaccine effectiveness estimates at the study design and analysis stages.
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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.