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Summary
This study examined the epidemiological characteristics and transmission patterns of 2143 pediatric patients with COVID-19, using a retrospective analytical approach.
What is known about this topic An increasing number of studies have focused on the novel coronavirus disease 2019 (COVID-19) since its outbreak, but few data are available on the epidemiological characteristics and transmission patterns of children with COVID-19. What this study adds
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Summary
Goals:
To identify the epidemiological characteristics and transmission patterns of pediatric patients with COVID-19 in China.
Methods:
Nationwide case series of 2,143 pediatric patients with COVID-19 reported to the Chinese Center for Disease Control and Prevention from January 16 to February 8, 2020 were included.
The epidemic curves were constructed according to the key dates of onset of the disease and the diagnosis of the case. Onset-to-diagnosis curves were constructed by fitting a log-normal distribution to data on onset and diagnosis dates.
Results:
- There were 731 (34.1%) laboratory confirmed cases and 1412 (65.9%) suspected cases.
- The median age of all patients was 7 years (interquartile range: 2-13), and 1213 cases (56.6%) were children.
- More than 90% of all patients were asymptomatic, mild or moderate cases .
- The median time from disease onset to diagnosis was 2 days (range: 0 to 42 days).
- There was a rapid increase in the disease in the early stage of the epidemic and then there was a gradual and steady decline.
- The disease spread rapidly from Hubei province to surrounding provinces over time. More children were infected in Hubei province than in any other province.
Discussion
To the best of our knowledge, this is the first retrospective study on the epidemiological characteristics and transmission dynamics of COVID-19 of children in China. As most of these children are likely to be exposed to family members and/or other children with COVID-19, this clearly indicates human-to-human transmission . Supporting evidence for such a transmission route has also been reported from studies in adult patients.
As of February 8, 2020, of the 2,143 pediatric patients included in this study, only one child died and most cases were mild , with much fewer severe and critical cases (5.9%) than adult patients (18). .5%) 13. Suggests that, compared to adult patients, the clinical manifestations of COVID-19 in children may be less severe.
Why most children’s COVID-19 cases were less severe than those of adults is puzzling.
This may be related to both exposure and host factors. Children were generally well cared for at home and might have relatively fewer opportunities to be exposed to pathogens and/or sick patients.
Angiotensin-converting enzyme II ( ACE2) was known as the cellular receptor of SARS-CoV.19 2019-nCoV has some amino acid homology with SARS-CoV and can use ACE2 as a receptor. Recent evidence indicates that ACE2 is also likely to be the cellular receptor for 2019-nCoV. It is speculated that children were less sensitive to 2019-nCoV because the maturity and function (e.g., binding capacity) of ACE2 in children may be lower than that in adults.
Additionally, children often experience respiratory infections (e.g., respiratory syncytial virus (RSV)) in winter and may have higher levels of virus antibodies than adults. Additionally, children’s immune systems are still developing and may respond to pathogens differently than adults.
However, we found that the proportion of severe and critical cases was 10.6%, 7.3%, 4.2%, 4.1% and 3.0% for the age group of ?1, 1-5, 6-10, 11-15 and > 15 years, respectively. These results suggest that young children, especially infants , were vulnerable to 2019-nCoV infection. Therefore, the mechanisms for the difference in clinical manifestations between children and adults remain to be determined.
There were more serious and critical cases in the suspected category than confirmed in this study. However, it remains to be determined whether these severe and critical cases in the suspected group were caused by 2019-nCoV or other pathogens (e.g., RSV). It may become clearer as the epidemic develops rapidly.
We observed slightly more boys than girls (56.6% vs. 43.4%) affected in the COVID-19 outbreak, which is similar to the two recent epidemiological studies. However, no significant gender differences were observed in this study.
The median age of all children’s COVID-19 cases was 7 years (interquartile range: 11), but ranged from 1 day to 18 years.
It suggests that all ages in childhood were susceptible to 2019-nCoV.
Conclusions:
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