High infection secondary attack rates of SARS-CoV-2 in Dutch households revealed by dense sampling.
TL;DR: In this paper, the authors investigated the role of households as one of the main multipliers of SARS-CoV-2 infection in the population, and showed that households represent a close-contact environment with high probability of transmission between persons of different ages and with different roles in society.
Abstract: BACKGROUND: Indoor environments are considered one of the main settings for transmission of SARS-CoV-2. Households in particular represent a close-contact environment with high probability of transmission between persons of different ages and with different roles in society. METHODS: Complete households with a laboratory-confirmed SARS-CoV-2 positive case in the Netherlands (March-May 2020) were included. At least three home visits were performed during 4-6 week of follow-up, collecting naso- and oropharyngeal swabs, oral fluid, feces and blood samples for molecular and serological analyses of all household members. Symptoms were recorded from two weeks before the first visit through to the final visit. Infection secondary attack rates (SAR) were estimated with logistic regression. A transmission model was used to assess transmission routes in the household. RESULTS: A total of 55 households with 187 household contacts were included. In 17 households no transmission took place, and in 11 households all persons were infected. Estimated infection SARs were high, ranging from 35% (95%CI: 24%-46%) in children to 51% (95%CI: 39%-63%) in adults. Estimated transmission rates in the household were high, with reduced susceptibility of children compared to adolescents and adults (0.67; 95%CI: 0.40-1.1). CONCLUSION: Estimated infection SARs were higher than reported in earlier household studies, presumably owing to our dense sampling protocol. Children were shown to be less susceptible than adults, but the estimated infection SAR in children was still high. Our results reinforce the role of households as one of the main multipliers of SARS-CoV-2 infection in the population.
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TL;DR: In this paper , the authors explored the household transmissibility of SARS-CoV-2 in children in new-variants dominating periods and found that younger children were as susceptible as older children (RR = 0.18-0.30).
32 citations
Academy of Athens1, French Institute of Health and Medical Research2, Rockefeller University3, University of Paris4, McGill University Health Centre5, University of Wisconsin-Madison6, Trinity College, Dublin7, University of Rome Tor Vergata8, Ghent University Hospital9, University of Barcelona10, Catalan Institution for Research and Advanced Studies11, National Institutes of Health12, Utrecht University13
TL;DR: In this article, a strategy for identifying, recruiting, and genetically analyzing individuals who are naturally resistant to SARS-CoV-2 infection was proposed, along with a genetic and immunological determinants of resistance to infection per se.
Abstract: SARS-CoV-2 infections display tremendous interindividual variability, ranging from asymptomatic infections to life-threatening disease. Inborn errors of, and autoantibodies directed against, type I interferons (IFNs) account for about 20% of critical COVID-19 cases among SARS-CoV-2-infected individuals. By contrast, the genetic and immunological determinants of resistance to infection per se remain unknown. Following the discovery that autosomal recessive deficiency in the DARC chemokine receptor confers resistance to Plasmodium vivax, autosomal recessive deficiencies of chemokine receptor 5 (CCR5) and the enzyme FUT2 were shown to underlie resistance to HIV-1 and noroviruses, respectively. Along the same lines, we propose a strategy for identifying, recruiting, and genetically analyzing individuals who are naturally resistant to SARS-CoV-2 infection.
31 citations
TL;DR: The role of children and young people (CYP) in transmission of SARS-CoV-2 in household and educational settings remains unclear as discussed by the authors , and a systematic review and meta-analysis of contact-tracing and population-based studies at low risk of bias was conducted.
30 citations
TL;DR: In this paper, the authors investigated the rate ratio of severe COVID-19 associated with eligibility for the shielding program in Scotland across the first and second waves of the epidemic and the relation of severe CoVid-19 to transmission-related factors in those in shielding and the general population.
Abstract: Clinically vulnerable individuals have been advised to shield themselves during the COVID-19 epidemic. The objectives of this study were to investigate (1) the rate ratio of severe COVID-19 associated with eligibility for the shielding programme in Scotland across the first and second waves of the epidemic and (2) the relation of severe COVID-19 to transmission-related factors in those in shielding and the general population. In a matched case-control design, all 178,578 diagnosed cases of COVID-19 in Scotland from 1 March 2020 to 18 February 2021 were matched for age, sex and primary care practice to 1,744,283 controls from the general population. This dataset (REACT-SCOT) was linked to the list of 212,702 individuals identified as eligible for shielding. Severe COVID-19 was defined as cases that entered critical care or were fatal. Rate ratios were estimated by conditional logistic regression. With those without risk conditions as reference category, the univariate rate ratio for severe COVID-19 was 3.21 (95% CI 3.01 to 3.41) in those with moderate risk conditions and 6.3 (95% CI 5.8 to 6.8) in those eligible for shielding. The highest rate was in solid organ transplant recipients: rate ratio 13.4 (95% CI 9.6 to 18.8). Risk of severe COVID-19 increased with the number of adults but decreased with the number of school-age children in the household. Severe COVID-19 was strongly associated with recent exposure to hospital (defined as 5 to 14 days before presentation date): rate ratio 12.3 (95% CI 11.5 to 13.2) overall. The population attributable risk fraction for recent exposure to hospital peaked at 50% in May 2020 and again at 65% in December 2020. The effectiveness of shielding vulnerable individuals was limited by the inability to control transmission in hospital and from other adults in the household. Mitigating the impact of the epidemic requires control of nosocomial transmission.
22 citations
TL;DR: In this paper , the authors used multiplex immunoassay data from 1,513 SARS-CoV-2 RT-qPCR-tested individuals (352 positive and 1,161 negative) without COVID-19 vaccination history to determine the accuracy of Nucleoprotein-specific immunoglobulin G (IgG) in detecting past severe acute respiratory syndrome coronavirus 2 infection.
21 citations