chuka_lis (chuka_lis) wrote,

Заразность детей

Исследователи из Массачуссетса выпустили препринт, в котором показали, что у заболевших ковидом детей вирус вырабатывается так же, как и у взрослых, в таких же количествах как минимум, причем вирус живой и отлично заражает культуры клеток.
Среди детей ходят такие же штаммы вируса, как и среди взрослых.
Наиболее заразны дети в первые 5 дней болезни.
Чем больше вируса обнаружено в количественном ПЦР, тем больше шансов, что он живой и культурируется.
Примерно четверть образцов вируса, которые культурировались после выделения, были от детей, которые были асимптоматичны (а таких в выборке было 27%)
Авторы считают, что дети потенциально могут быть резервуаром для активно размножающегося вируса в популяции, и такая ситуация будет способствовать и зарождению новых волн эпидемии,  и появлению новых штаммов.
To date, roughly4 million childrenin the Unites States havebeen reported as testing positive forCOVID-19[3].Children under 19 years of agenow represent the age group with the highest rate of infection in some regions[4].Most children generally have milder symptoms when infected with SARS-CoV-2[5], although a small subset of individualsdevelop severe disease. In the US, over 16,000 children have been hospitalized for acute COVID-19 with over 300 deaths reported[3]. A baseline understanding of infection in children is a necessary prerequisite to understanding the pathogenesis of severe presentations of COVID-19.
Atapopulation perspective, the role that children play in viral transmission remains poorly understood. Epidemiologic studies suggest that children exhibit lower transmission rates than adults[6], however, these findings are potentially confounded by higher rates of asymptomatic or pauci-symptomatic infection in children, increased social isolation by children early in the pandemic, and reduced COVID-19 testing in children.Our data indicate that age, from infancy through adulthood,is not a predictor of viral infection dynamics, and that children of all ages can have high SARS-CoV-2 viral loadsof replication-competent virus,including variants, displaying comparable dynamicsto thoseseenin adults.
Methods: Nasal swabs collected from children with COVID-19 were analyzed. Viral load was quantified by RT-PCR; viral culture was assessed by direct observation of cytopathic effects and semiquantitative viral titers. Correlations with age or symptom duration were analyzed. SARS-CoV-2 whole genome amplification was compared with contemporaneous Massachusetts sequences to assess for clustering patterns. Results: Ninety-seven children with COVID-19 (median age 10 years, range 2 weeks-22 years) were included in this study. Age did not impact SARS-CoV-2 viral load in nasal secretions: children of all ages were equally likely to carry live, replicating virus. Children within the first five days of illness had higher viral loads and rates of culture positivity, and viral load in hospitalized children (n=30) did not differ from hospitalized adults (n=21) with similar duration of symptoms. While pediatric SARS-CoV-2 sequences were representative of those in the community, novel variants were identified. Conclusions: Children can carry high quantities of live, replicating virus, creating a potential reservoir for transmission and evolution of genetic variants. As guidance around social distancing and masking evolves following vaccine uptake in older populations, a clear understanding of SARS-CoV-2 infection dynamics in children is critical for rational development of public health policies and vaccination strategies to mitigate the impact of COVID-19.  
ur results additionally suggest that pediatric populations have the potential to serve as a community reservoir of actively replicating virus, with implications for both new waves of infection and the evolution of viral variants. The duration of natural and vaccine-induced immunity for each vaccine in clinical use are not yet known. If a community reservoir of actively replicating virus is maintained and transmitted within unvaccinated pediatric populations, that population couldthen serveas a source of newinfections as vaccine-induced immunity wanesin vaccinated adult populations. In addition, viral genomic variantswere readily identified in the pediatric samples and these variants have the potential to impact viral transmission[21-23], disease severity[24, 25], and vaccine efficacy[26]. Ongoing viral replication within pediatric populations has the potential to serve as a source of existing and new viral variants that interfere with eradication efforts. Ultimately our results underline the importance of defining public health policy with viral dynamics inchildren in mind and of including pediatric populations in vaccine efforts aimed at eradication.
Tags: дети, коронавирус, статьи, эпидемия
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