ArticleEmerging infectious diseases2022
SARS-CoV-2 Secondary Attack Rates in Vaccinated and Unvaccinated Household Contacts during Replacement of Delta with Omicron Variant, Spain.
Article in Emerging infectious diseases, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 14 papers.
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Who cites it
14 citing papers in PubMed.
- Oral Nirmatrelvir-Ritonavir as Postexposure Prophylaxis for Covid-19.The New England journal of medicine · 2024Trial
- Article
- SARS-CoV-2 mRNA Vaccine Effectiveness in the Borriana COVID-19 Cohort: A Prospective Population-Based Cohort Study.Epidemiologia (Basel, Switzerland) · 2025Article
- Mask wearing by COVID-19 index cases reduces SARS-CoV-2 transmission to household contacts.Epidemiology and infection · 2025Article
- Effectiveness of inactivated COVID-19 vaccine against symptom severity in hospitalized COVID-19 patients infected with the Omicron variant.Archives of virology · 2025Article
- Modelling the effectiveness of antiviral treatment strategies to prevent household transmission of acute respiratory viruses.PLoS computational biology · 2024Article
- Overestimation of Severe Acute Respiratory Syndrome Coronavirus 2 Household Transmission in Settings of High Community Transmission: Insights From an Informal Settlement Community in Salvador, Brazil.Open forum infectious diseases · 2024Article
- Vaccinated COVID-19 Index Cases Are Less Likely to Transmit SARS-CoV-2 to Their Household Contacts: A Cohort Study.Vaccines · 2024Article
- Article
- Environmental predictors of SARS-CoV-2 infection incidence in Catalonia (northwestern Mediterranean).Frontiers in public health · 2024Article
- Assessing the effects of SARS-CoV-2 vaccination on the risk of household transmission during delta variant circulation: a population-based data linkage cohort study.The Lancet regional health. Western Pacific · 2024Article
- Absence of short-term changes in knowledge and attitudes among household contacts of COVID-19 cases during the post-acute phase of the pandemic in Catalonia and Navarre, Spain.Frontiers in public health · 2024Article
- Household secondary attack rates and risk factors during periods of SARS-CoV-2 Delta and Omicron variant predominance in the Republic of Korea.Osong public health and research perspectives · 2023Article
- Case clustering, contact stratification, and transmission heterogeneity of SARS-CoV-2 Omicron BA.5 variants in Urumqi, China: An observational study.Journal of global health · 2023Observational
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13 authors.
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Abstract
We performed a prospective, cross-sectional study of household contacts of symptomatic index case-patients with SARS-CoV-2 infection during the shift from Delta- to Omicron-dominant variants in Spain. We included 466 household contacts from 227 index cases. The secondary attack rate was 58.2% (95% CI 49.1%-62.6%) during the Delta-dominant period and 80.9% (95% CI 75.0%-86.9%) during the Omicron-dominant period. During the Delta-dominant period, unvaccinated contacts had higher probability of infection than vaccinated contacts (odds ratio 5.42, 95% CI 1.6-18.6), but this effect disappeared at ≈20 weeks after vaccination. Contacts showed a higher relative risk of infection (9.16, 95% CI 3.4-25.0) in the Omicron-dominant than Delta-dominant period when vaccinated within the previous 20 weeks. Our data suggest vaccine evasion might be a cause of rapid spread of the Omicron variant. We recommend a focus on developing vaccines with long-lasting protection against severe disease, rather than only against infectivity.
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