Seroprevalence of SARS-CoV-2 antibodies and associated risk factors in children less than 6 years of age in the canton of Fribourg, Switzerland (COVPED study): a population-based cross-sectional study.

BACKGROUND: To date, few data are available about severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in young children and the role of early-life childcare arrangements in transmission of the virus. In this study, we assessed the SARS-CoV-2 seroprevalence in children less than 6 years of age in the canton of Fribourg and identified risk factors associated with seropositivity. METHODS: The COVPED study is a population-based cross-sectional study in children less than 6 years of age living in the canton of Fribourg, Switzerland, who presented to a private paediatrician or the paediatric emergency department of the Fribourg Hospital during a 9-week period between 11 January and 14 March 2021. Immunoglobulin G antibodies against SARS-CoV-2 trimeric spike protein were measured in capillary blood samples using an in-house Luminex assay. A mean fluorescence intensity ratio of above 6 was considered as positive. Metadata was collected through electronic questionnaires. Logistic regression analysis was performed to assess the risk of seropositivity and associated factors. RESULTS: A total of 871 children, with a median age of 33 months (range 6 days to 5 years 11 months) were included; 412 (47%) were female. Overall, 180 (21%, 95% confidence interval [CI] 18-24%) children were seropositive. Age as continuous variable was not associated with seropositivity risk, apart from a higher rate in children less than 3 months of age. Univariable analysis showed that female sex was associated with a lower seropositivity risk (unadjusted odds ratio [OR] 0.69, 95% CI 0.49-0.96; p = 0.03). Day-care attendance was also associated with a lower seropositivity risk (OR 0.67, 95% CI 0.47-0.95; p = 0.03), whereas all other childcare arrangements were not associated with seropositivity. No association was found between the number of children and adults present in extra-familial care and seropositivity. Multivariable analysis identified the number of household members above the age of 12 years being positive for SARS-CoV-2 as the main risk factor for seropositivity in children (adjusted odds ratio [aOR] 7.80, 95% CI 4.65-13.07; p <0.001 for one household member, aOR 22.07, 95% CI 13.49-36.11; p <0.001 for two household members and aOR 32.20, 95% CI 9.30-111.55; p <0.001 for three or more household members). CONCLUSION: The number of household members tested positive for SARS-CoV-2 (PCR test) is the main exposure risk to seropositivity for children less than 6 years of age. But the family size is not associated with an increased risk of infection. In young children, extra-familial care does not increase the risk of becoming SARS-CoV-2 seropositive, neither does the number of contacts present in extra-familial care. As adults and children will be vaccinated and new virus variants will be circulating the risk of exposure for young children will likely change and needs further monitoring.

[Physiological respiratory changes and venous thromboembolic disease during pregnancy]. / Modifications respiratoires physiologiques et maladie thromboembolique veineuse lors de la grossesse.

During physiological pregnancy, changes in lung functions, ventilatory patterns and gas exchanges happen. Therefore, the dyspnea experienced by a majority of women is usually due to pregnancy itself and is very difficult to differentiate from a pathophysiological state. Anamnesis and clinical examination alone do not rule out dyspnea of ​​thromboembolic origin. Therefore, a structured approach, based on a thromboembolic risk assessment, the application of a specific management algorithm and the use of imaging exams is required for emergency management of dyspnea occurring during the pregnancy and in the postpartum.

Durant une grossesse physiologique, des modifications des fonctions pulmonaires, des paramètres ventilatoires et des échanges gazeux surviennent. Dès lors, la dyspnée ressentie par une majorité des femmes est généralement due à la grossesse elle-même et peut être difficile à différencier d'un état physiopathologique. L'anamnèse et l'examen clinique seuls ne permettent pas d'écarter une dyspnée d'origine thromboembolique. Par conséquent, lors de la prise en charge aux urgences d'une dyspnée survenant pendant la grossesse ou le postpartum, une approche structurée, basée sur une évaluation du risque thromboembolique, l'application d'un algorithme de prise en charge spécifique et des examens d'imagerie, est requise.