ArticleThe Lancet regional health. Europe2022
Impact of SARS-CoV-2 Delta variant on incubation, transmission settings and vaccine effectiveness: Results from a nationwide case-control study in France.
Article in The Lancet regional health. Europe, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 87 papers, 5 of them syntheses that pooled it.
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
87 citing papers in PubMed, 5 syntheses or guidelines pooled it, 155 citations in OpenAlex.
- Assessing changes in incubation period, serial interval, and generation time of SARS-CoV-2 variants of concern: a systematic review and meta-analysis.BMC medicine · 2023Pooled it
- Risk factors for SARS-CoV-2 infection during the early stages of the COVID-19 pandemic: a systematic literature review.Frontiers in public health · 2023Pooled it
- Incubation Period of COVID-19 Caused by Unique SARS-CoV-2 Strains: A Systematic Review and Meta-analysis.JAMA network open · 2022Pooled it
- Effectiveness of COVID-19 vaccines against SARS-CoV-2 variants of concern: a systematic review and meta-analysis.BMC medicine · 2022Pooled it
- Real-Word Effectiveness of Global COVID-19 Vaccines Against SARS-CoV-2 Variants: A Systematic Review and Meta-Analysis.Frontiers in medicine · 2022Pooled it
- The effectiveness of COVID-19 vaccines and the added benefit of booster doses in Hessen, Germany, during the COVID-19 pandemic: Results from a vaccinated-only study.Human vaccines & immunotherapeutics · 2026Article
- Machine learning and probabilistic approaches for forecasting infectious disease transmission and cases.International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases · 2026Article
- A Multi-Region SEIR Model Incorporating Inter-County Mobility and Time-Dependent Transmission Dynamics: Application to COVID-19 Disease Outbreak Data in North Carolina.Bulletin of mathematical biology · 2026Article
- Effectiveness of a single COVID-19 mRNA vaccine dose in individuals with prior SARS-CoV-2 infection: a systematic review.Communications medicine · 2025Article
- A Flexible Framework for Local-Level Estimation of the Effective Reproductive Number in Geographic Regions with Sparse Data.medRxiv : the preprint server for health sciences · 2025Article
- Correlates of Protection Against Symptomatic COVID-19: The CORSER 5 Case-Control Study.Open forum infectious diseases · 2025Article
- Adaptive vaccination and surveillance testing strategies for infectious diseases with diverse strain dynamics.Health systems (Basingstoke, England) · 2025Article
- A novel comparison framework for epidemiological strategies applied to age-based restrictions versus horizontal lockdowns.Infectious Disease Modelling · 2024Article
- Risk of SARS-CoV-2 infection in professional settings, shops, shared transport, and leisure activities in France, 2020-2022.BMC public health · 2024Observational
- Redefining pandemic preparedness: Multidisciplinary insights from the CERP modelling workshop in infectious diseases, workshop report.Infectious Disease Modelling · 2024Review
- Vertical transmission of SARS-CoV-2 delta-variant in a preterm infant.BMC infectious diseases · 2024Article
- A Bayesian framework for modeling COVID-19 case numbers through longitudinal monitoring of SARS-CoV-2 RNA in wastewater.Statistics in medicine · 2024Article
- Detecting changes in generation and serial intervals under varying pathogen biology, contact patterns and outbreak response.PLoS computational biology · 2024Article
- Article
- Feature selection for effective prediction of SARS-COV-2 using machine learning.Genes & genomics · 2024Article
27 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
17 authors at 6 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundWe aimed to assess the settings and activities associated with SARS-CoV-2 infection in the context of B.1.617.2 (Delta) variant circulation in France, as well as the protection against symptomatic Delta infection.
methodsIn this nationwide case-control study, cases were SARS-CoV-2 infected adults recruited between 23 May and 13 August 2021. Controls were non-infected adults from a national representative panel matched to cases by age, sex, region, population density and calendar week. Participants completed an online questionnaire and multivariable logistic regression analysis was used to determine the association between acute SARS-CoV-2 infection and recent activity-related exposures, past history of SARS-CoV-2 infection, and COVID-19 vaccination.
findingsWe did not find any differences in the settings and activities associated with Delta versus non-Delta infections and grouped them for subsequent analyses. In multivariable analysis involving 12634 cases (8644 Delta and 3990 non-Delta) and 5560 controls, we found individuals under 40 years and attending bars (aOR:1.9; 95%CI:1.6-2.2) or parties (aOR:3.4; 95%CI:2.8-4.2) to be at increased risk of infection. In those aged 40 years and older, having children attend daycare (aOR:1.9; 95%CI:1.1-3.3), kindergarten (aOR:1.6; 95%CI:1.2-2.1), primary school (aOR:1.4; 95%CI:1.2-1.6) or middle school (aOR:1.3; 95%CI:1.2-1.6) were associated with increased risk of infection. We found strong protection against symptomatic Delta infection for those with prior infection whether it was recent (2-6 months) (95%; 95%CI:90-97) or associated with one dose (85%; 95%CI:78-90) or two doses of mRNA vaccine (96%; 95%CI:87-99). For those without past infection, protection was lower with two doses of mRNA vaccine (67%; 95%CI:63-71).
interpretationIn line with other observational studies, we find reduced vaccine effectiveness against symptomatic Delta infections. The settings and activities at increased risk of infection indicate where efforts to reinforce individual and public health measures need to be concentrated.
Identifiers
What OpenQuestion holds
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.