ArticleNature medicine2022
Effectiveness of CoronaVac in children 3-5 years of age during the SARS-CoV-2 Omicron outbreak in Chile.
Article in Nature medicine, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 69 papers, 6 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
69 citing papers in PubMed, 6 syntheses or guidelines pooled it, 96 citations in OpenAlex.
- The effect of COVID-19 vaccine to the Omicron variant in children and adolescents: a systematic review and meta-analysis.Frontiers in public health · 2024Pooled it
- Immunogenicity, effectiveness, and safety of COVID-19 vaccines among children and adolescents aged 2-18 years: an updated systematic review and meta-analysis.World journal of pediatrics : WJP · 2023Pooled it
- Effectiveness of homologous or heterologous immunization regimens against SARS-CoV-2 after two doses of inactivated COVID-19 vaccine: A systematic review and meta-analysis.Human vaccines & immunotherapeutics · 2023Pooled it
- Real-world effectiveness and factors associated with effectiveness of inactivated SARS-CoV-2 vaccines: a systematic review and meta-regression analysis.BMC medicine · 2023Pooled it
- Effectiveness of COVID-19 vaccine in children and adolescents with the Omicron variant: A systematic review and meta-analysis.The Journal of infection · 2023Pooled it
- Effectiveness and Cost-Effectiveness of Inactivated Vaccine to Address COVID-19 Pandemic in China: Evidence From Randomized Control Trials and Real-World Studies.Frontiers in public health · 2022Pooled it
- Immunogenicity and safety of CoronaVac vaccine in children and adolescents (Immunita-002, Brazil): A phase IV six-month follow up.Scientific reports · 2025Trial
- Efficacy, immunogenicity and safety of CoronaVac® in children and adolescents aged 6 months to 17 years: a multicenter, randomized, double-blind, placebo-controlled phase III clinical trial.Nature communications · 2024Trial
- Immunogenicity, safety and consistency of seven lots of an inactivated COVID-19 vaccine in healthy children and adolescents: a randomized, double-blind, controlled, phase IV clinical trial.Frontiers in immunology · 2023Trial
- Institutional quality and pandemic resilience: cross-country evidence on health and economic outcomes during COVID-19.Globalization and health · 2026Article
- Single-cell transcriptomics reveals pediatric immune responses to COVID-19 vaccination.iScience · 2026Article
- Clinical characteristics of acute lower respiratory tract infection caused by Omicron, respiratory syncytial virus, and influenza virus a in children in Chengdu: a retrospective study.Italian journal of pediatrics · 2025Article
- Research progress in vaccination during pregnancy.Frontiers in immunology · 2025Review
- Evaluation of humoral and cellular immune responses in healthcare workers with varying levels of SARS-CoV-2 exposure: effects of CoronaVac vaccination followed by heterologous booster.Frontiers in immunology · 2025Article
- Effectiveness of inactivated COVID-19 vaccines in preventing COVID-19-related hospitalization during the Omicron BF.7-predominant epidemic wave in Beijing, China: a cohort study.BMC infectious diseases · 2024Article
- Article
- Booster Vaccination with BNT162b2 Improves Cellular and Humoral Immune Response in the Pediatric Population Immunized with CoronaVac.Vaccines · 2024Article
- Trimerized S expressed by modified vaccinia virus Ankara (MVA) confers superior protection against lethal SARS-CoV-2 challenge in mice.Journal of virology · 2024Article
- Real-world effectiveness of the heterologous SOBERANA-02 and SOBERANA-Plus vaccine scheme in 2-11 years-old children during the SARS-CoV-2 Omicron wave in Cuba: a longitudinal case-population study.Lancet regional health. Americas · 2024Article
- Update on Omicron variant and its threat to vulnerable populations.Public health in practice (Oxford, England) · 2024Review
9 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 4 institutions in 3 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The outbreak of the B.1.1.529 lineage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (Omicron) has caused an unprecedented number of Coronavirus Disease 2019 (COVID-19) cases, including pediatric hospital admissions. Policymakers urgently need evidence of vaccine effectiveness in children to balance the costs and benefits of vaccination campaigns, but, to date, the evidence is sparse. Leveraging a population-based cohort in Chile of 490,694 children aged 3-5 years, we estimated the effectiveness of administering a two-dose schedule, 28 days apart, of Sinovac's inactivated SARS-CoV-2 vaccine (CoronaVac). We used inverse probability-weighted survival regression models to estimate hazard ratios of symptomatic COVID-19, hospitalization and admission to an intensive care unit (ICU) for children with complete immunization over non-vaccination, accounting for time-varying vaccination exposure and relevant confounders. The study was conducted between 6 December 2021 and 26 February 2022, during the Omicron outbreak in Chile. The estimated vaccine effectiveness was 38.2% (95% confidence interval (CI), 36.5-39.9) against symptomatic COVID-19, 64.6% (95% CI, 49.6-75.2) against hospitalization and 69.0% (95% CI, 18.6-88.2) against ICU admission. The effectiveness against symptomatic COVID-19 was modest; however, protection against severe disease was high. These results support vaccination of children aged 3-5 years to prevent severe illness and associated complications and highlight the importance of maintaining layered protections against SARS-CoV-2 infection.
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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.