IMPORTANCE Solid estimates of the risk of developing symptoms and of progressing to critical disease in individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are key to interpreting coronavirus disease 2019 (COVID-19) dynamics, identifying the settings and the segments of the population where transmission is more likely to remain undetected, and defining effective control strategies. OBJECTIVE To estimate the association of age with the likelihood of developing symptoms and the association of age with the likelihood of progressing to critical illness after SARS-CoV-2 infection. DESIGN, SETTING, AND PARTICIPANTS This cohort study analyzed quarantined case contacts, identified between February 20 and April 16, 2020, in the Lombardy region of Italy. Contacts were monitored daily for symptoms and tested for SARS-CoV-2 infection, by either real-time reverse transcriptase-polymerase chain reaction using nasopharyngeal swabs or retrospectively via IgG serological assays. Close contacts of individuals with laboratory-confirmed COVID-19 were selected as those belonging to clusters (ie, groups of contacts associated with an index case) where all individuals were followed up for symptoms and tested for SARS-CoV-2 infection. Data were analyzed from February to June 2020. EXPOSURE Close contact with individuals with confirmed COVID-19 cases as identified by contact tracing operations. MAIN OUTCOMES AND MEASURES Age-specific estimates of the risk of developing respiratory symptoms or fever greater than or equal to 37.5°C and of experiencing critical disease (defined as requiring intensive care or resulting in death) in SARS-CoV-2-infected case contacts. RESULTS In total, 5484 case contacts (median [interquartile range] age, 50 [30-61] years; 3086 female contacts [56.3%]) were analyzed, 2824 of whom (51.5%) tested positive for SARS-CoV-2 (median [interquartile range] age, 53 [34-64] years; 1604 female contacts [56.8%]). The proportion of infected persons who developed symptoms ranged from 18.1% (95% CI, 13.9%-22.9%) among participants younger than 20 years to 64.6% (95% CI, 56.6%-72.0%) for those aged 80 years or older. Most infected contacts (1948 of 2824 individuals [69.0%]) did not develop respiratory symptoms or fever greater than or equal to 37.5°C. Only 26.1% (95% CI, 24.1%-28.2%) of infected individuals younger than 60 years developed respiratory symptoms or fever greater than or equal to 37.5°C; among infected participants older than 60 years, 6.6% (95% CI, 5.1%-8.3%) developed critical disease. Female patients were 52.7% (95% CI, 24.4%-70.7%) less likely than male patients to develop critical disease after SARS-CoV-2 infection. (continued) Key Points Question What is the association of age Open Access. This is an open access article distributed under the terms of the CC-BY License.

Employment, union formation and childbearing are central processes within young individuals' transition to adulthood. These processes interact in highly complex ways, and they shape actual life-course trajectories that may be seen as a conceptual unit. In this article we use a methodology to cluster life-course experiences, where all three processes are embedded explicitly, in order to study young women's trajectories in Great Britain. Drawing on a sample from the British Household Panel Survey (BHPS), we define life-courses as sequences on a monthly time scale and we apply optimal matching analysis to compute dissimilarities between individuals. We then use standard clustering algorithms and we identify nine distinctive groups of women. Our results are then shown using a new representation of clusters and interpreted in the light of the existing socio-demographic literature on the dynamic work-family link.Keywords Work-family trajectories Á Sequence analysis Á Transition to adulthood Á Life-course analysis Á BHPS Résumé Le travail, la mise en union et la procréation sont des processus centraux dans le passage vers l'âge adulte. Ces processus interagissent de manière très complexe, et modèlent les trajectoires biographiques, qui peuvent être considérées comme une unité conceptuelle. Dans cet article, nous utilisons une méthodologie pour catégoriser des expériences biographiques, en considérant que les 3 processus sont explicitement imbriqués, de manière à étudier les trajectoires des jeunes femmes en Grande Bretagne. A partir d'un échantillon du Panel Britannique des Ménages («BHPS»), la biographie est découpée en séquences sur une base mensuelle, et une analyse d'appariement optimale est appliquée pour calculer les dissemblances entre individus. Des algorithmes d'analyse de groupes sont ensuite utilisés, permettant d'identifier 9 groupes distincts de femmes. Les résultats sont illustrés à l'aide d'une nouvelle représentation des groupes, et interprétés à la lumière de la littérature sociodémographique sur la dynamique des relations famille-travail.

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IMPORTANCE Identifying health care settings and professionals at increased risk of SARS-CoV-2 infection is crucial to defining appropriate strategies, resource allocation, and protocols to protect health care workers (HCWs) and patients. Moreover, such information is crucial to decrease the risk that HCWs and health care facilities become amplifiers for SARS-CoV-2 transmission in the community. OBJECTIVE To assess the association of different health care professional categories and operational units, including in-hospital wards, outpatient facilities, and territorial care departments, with seroprevalence and odds of SARS-CoV-2 infection. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional study was conducted using IgG serological tests collected from April 1 through May 26, 2020, in the Lombardy region in Italy. Voluntary serological screening was offered to all clinical and nonclinical staff providing any health care services or support to health care services in the region. Data were analyzed from June 2020 through April 2021. EXPOSURES Employment in the health care sector. MAIN OUTCOMES AND MEASURES Seroprevalence of positive IgG antibody tests for SARS-CoV-2 was collected, and odds ratios of experiencing infection were calculated. RESULTS A total of 140 782 professionals employed in the health sector were invited to participate in IgG serological screening, among whom 82 961 individuals (59.0% response rate) were tested for SARS-CoV-2 antibodies, with median (interquartile range [IQR]; range) age, 50 (40-56; 19-83) years and 59 839 (72.1%) women. Among these individuals, 10 115 HCWs (12.2%; 95% CI, 12.0%-12.4%) had positive results (median [IQR; range] age, 50 [39-55; 20-80] years; 7298 [72.2%] women).

We analysed 5,484 close contacts of coronavirus disease (COVID-19) cases in Italy, all tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Infection fatality ratio was 0.43% (95% confidence interval (CI): 0.21–0.79) for individuals younger than 70 years and 10.5% (95% CI: 8.0–13.6) for older individuals. Risk of death after infection was 62% lower (95% CI: 31–80) in clusters identified after 16 March 2020 and 1.8-fold higher for males (95% CI: 1.03–3.16).