子どものCoVID-19に対するリスク

中国の子どものCOVID-19に関する新たな疫学報告は、彼らが成人よりも感染して重度の病気にかかる可能性は低いが、SARSｰCoV2に対して依然として脆弱であることを示しています。

今日(3月19日)、Pediatricsで発表された大規模な研究は、武漢とその周辺地域のすべての年齢の子どもがCOVID-19ウイルスに感染しやすく、1人（14歳の少年）が死亡したことを示しました。

また、今日のNature Medicineに掲載されたCOVID-19の重症度に関する報告の中で、研究者は武漢の子どもたちが30〜59歳の成人よりもウイルスに感染し、死亡する可能性が低いことを報告しました。

昨日、NEJMで発表された報告によると、武漢の病院の小児患者171人のうち、ほぼ4分の1が症状がなく、死亡したのは1人だけでした。

子どものCoVID-19は一般に深刻ではないが、どの年齢も重症化をまぬがれない。

Pediatricsの研究では、研究者は、中国の疾病管理予防センター（中国CDC）に1月16日から2月8日までに報告された2,143の確認済み、または可能性のある小児COVID-19感染症の病気の広がりと重症度の最初の後方視的疫学分析を実施しました。

2,143例のうち、731例（34.1％）が検査で確認され、1,412例（65.9％）が疑われました。

患者の年齢の中央値は7歳（範囲は日齢1から18歳まで）でした。 1,213（56.6％）は男子でした。

臨床徴候、検査室検査、および胸部X線を使用して、研究者たちは

94人（4.4％）が無症状、

1,091人（50.9％）が軽度、

831人（38.8％）が中等度、

に分類した。

年少の子どもたちは、年長の子どもたちよりも深刻な病気のリスクが高かった。

重症例と危篤症例の割合は、

1歳未満で10.6％、

1〜5歳で7.3％、

6〜10歳で4.2％、

11〜15歳で4.1％、

16〜18歳で3.0％でした。

「死亡した子供は1人だけで、ほとんどの症例は軽度であり、

成人患者（18.5％）よりも重症患者および危篤患者（5.9％）がはるかに少ない」

と彼らは書いた。

その発見にもかかわらず、研究者は、すべての年齢の男女がコロナウイルスのために明らかに危険にさらされていると述べた。

「小児のCOVID-19症例の臨床症状は一般に成人患者よりも軽度でしたが、

若い小児患者、特に乳幼児は感染症に脆弱でした」

と彼らは書いています。

著者は、

「軽い症状の原因は、冬の呼吸器感染症へのより広範な曝露により、COVID-19への曝露または感受性の低下、異なる免疫応答メカニズム、または成人よりも高いレベルのウイルス抗体に起因する可能性がある」

と書いています。

Pediatricsの編集者であるAndrea Cruz　MD、Steven Zeichner, MD、PhDは、同じ号で、

一方、パンデミックの研究は経済的生産性が高い大人を対象とすることが多く、病気が大人と子どもに異なる影響を与えることを理解すると、『病気の病因に関する重要な洞察が得られ、管理と治療法の開発が可能になります』

と解説しています。

病気の発症から診断までの期間の中央値は2日間でした（範囲、0〜42日）。

症例は1月中旬から2月上旬まで湖北省で急速に蓄積し、その後漸減しました。

湖北省の子どもたちは、他の州の子たちよりも多く感染しましたが、ウイルスはすぐに近隣地域に広がりました。

著者らは、「アウトブレイクの発生時に子どもたちが武漢の海鮮市場を訪れた可能性は低い」と指摘した。

「黒竜江省を除き、湖北省およびその周辺地域では、遠くの地域よりも子どもへの感染が多かった。」

と彼らは書いています。

「これらの子どもの殆どは、家族に感染させたり、COVID-19に感染している他の子どもと接触する可能性が高いため、人から人への感染を媒介していることを明確に示しています。」

感染や死亡の可能性が低い。

軽症の人々は武漢の健康システムで検査された可能性が低いため、Natureの研究者は、1月19日までの商業便および1月29日から2月4日までのチャーター便による都市へ病気の真の有病率を推定します。

彼らはまた、最初の425件の確認された症例のデータを使用して、病気の再生産数を推定しました。

30歳未満の人は30歳から59歳の人よりも感染で死亡する可能性が40％低い（0.6倍、95％信頼区間:0.3〜1.1）ことを、彼らは発見しました。

59歳以上の人は、死亡率が5.1倍（4.2〜6.1倍）でした。

CoVID-19の症状が出るリスクは年齢と共に増加し、30〜60歳の成人では年に約4％の率で上昇します。

CoVID-19の症状があった後に死亡する全体的なリスクは1.4％（0.9％〜2.1％）でした。

病気の発症から死亡までの平均期間は20日でした（17〜24日；標準偏差は10日[7〜14日]）。

30歳未満の人も、30歳から59歳の人よりも症候性感染症の可能性が84％低く（0.16倍、0.15ｰ0.17倍）、

59歳よりも高齢の人は2.0（1.95ｰ2.08）倍、症候性感染が高い可能性がありました。

ただし、子どもは、20〜29歳の成人よりも症候性感染症の可能性が高かった。

「症候性感染症（感受性）および転帰（致死性）のリスクには、それぞれの場合に複数の折り畳みにより、明確でかなりの年齢依存性がある」と研究者らは述べた。

「以前に報告されたパンデミックまたは季節性インフルエンザとは異なり、年齢とともに症候性感染のリスクも増加することがわかりましたが、この理由は、より高齢だったり、より重症例の優先的な検査によるものかもしれません。」

トリアージと診断では、症状の範囲、疾患の重症度、および予後を理解することが重要です。

「特に実験室でのテストにすぐにアクセスできない環境や、サージ容量を超えた場合」と著者は書いています。

それはまた、臨床医が供給とスタッフを適切に管理するための最良の治療と健康システムのリーダーを選ぶのを助けます。

大規模に、診断された感染と診断されていない感染の両方を推定することは、彼らが引き起こす可能性のある深刻な社会的および経済的混乱に照らして公衆衛生封じ込め戦略を知らせるのに役立ちます、と著者は書いています。

死亡は1例のみ

NEJMの研究では、研究者は中国CDCのデータを使用して、武漢の唯一の指定されたCOVID-19小児病院で感染が確認された、または感染の可能性がある人と接触した症候性および無症候性の子どもを評価しました。

1月28日から2月26日までに検査された1,391人の子供のうち、171人（12.3％）が感染を確認され、

1人（0.6％）がこの病気で死亡しました。

感染した子供の年齢の中央値は6.7歳でした。

多く（41.5％）が発熱し、咳と咽頭発赤も一般的でした。

22.8％が無症候性で、

27人（15.8％）はX線で肺炎の症状または徴候を示さず、

12人（7.0％）はX線で徴候を示したが症状はありませんでした。

「これらの無症候性患者の伝播の可能性を決定することは、進行中のパンデミックを制御するための対策の開発を導くために重要です」と著者らは書いた。

6人の患者（3.5％）で低リンパ球レベルが見つかりましたが、

X線では32.7％で両方の肺に体液蓄積の領域が見られました。

基礎疾患を抱える3人の患者は、集中治療と機械的換気が必要でした。

併存疾患には、水腎症（尿貯留による腎臓の肥大）、白血病（化学療法の受診を含む）、および腸重積症（腸閉塞）が含まれていました。

10ヶ月の腸重積症の子どもは多臓器不全を起こし、入院4週間後に死亡しました。

3月8日の時点で、21人の患者はICU以外のベッドで安定した状態にあり、

報告によると149人が退院していた。

Children's COVID-19 risks unique, Chinese studies find

Filed Under: COVID-19

Mary Van Beusekom | News Writer | CIDRAP News | Mar 19, 2020

http://www.cidrap.umn.edu/news-perspective/2020/03/childrens-covid-19-risks-unique-chinese-studies-find

Editor's Note: This story was corrected on Mar 20 to note that, in the Nature Medicine study, children were less likely to die and have a symptomatic infection than older groups, as the original said they were more likely to die and have a symptomatic infection. We apologize for the error.

Emerging epidemiologic reports on COVID-19 in children in China show that, while they are less likely than adults to be infected and have severe illness, they are still vulnerable to the pandemic coronavirus.

Today, a large study published in today's Pediatrics showed that children of all ages in Wuhan and surrounding areas were susceptible to the COVID-19 virus, and one—a 14-year-old boy—died from it.

Also, in a letter on the severity of COVID-19 published in today's Nature Medicine, researchers reported finding that children in Wuhan were less likely to be infected by the virus and to die from it than were adults 30 to 59 years old.

And among 171 pediatric patients at a hospital in Wuhan, almost a quarter had no symptoms and only 1 died, according to a letter published yesterday in the New England Journal of Medicine (NEJM).

Less severe illness in kids, but no ages spared

In the Pediatrics study, researchers conducted the first retrospective epidemiologic analysis of disease spread and severity in 2,143 confirmed or possible pediatric COVID-19 infections reported to the Chinese Center for Disease Control and Prevention (China CDC) from Jan 16 to Feb 8.

Of the 2,143 cases, 731 (34.1%) were laboratory-confirmed, and 1,412 (65.9%) were suspected. Median patient age was 7 years (range, 1 day to 18 years); 1,213 (56.6%) were boys.

Using clinical signs, lab testing, and chest x-rays, the researchers classified 94 patients (4.4%) as asymptomatic, 1,091 (50.9%) having mild disease, and 831 (38.8%) having moderate illness.

Young children were more at risk of serious illness than older children were. The proportion of severe and critical cases was 10.6 % for children younger than 1 year, 7.3% for those 1 to 5, 4.2% for those 6 to 10, 4.1% for those 11 to 15, and 3.0% for those 16 to 18. "Only one child died, and most cases were mild, with much fewer severe and critical cases (5.9%) than adult patients (18.5%)," they wrote.

Despite that finding, investigators said that children of all ages and both sexes were clearly at risk due to the coronavirus. "Although clinical manifestations of children's COVID-19 cases were generally less severe than those of adult patients, young children, particularly infants, were vulnerable to infection," they wrote.

The authors write that the less severe presentation may be attributed to less exposure or sensitivity to COVID-19, different immune response mechanisms, or higher levels of antibodies to viruses than in adults due to broader exposures to respiratory infections in winter.

In a commentary in the same issue, Pediatrics editors Andrea Cruz, MD, MPH, and Steven Zeichner, MD, PhD, said that, while studies of pandemics often center on adults because they are economically productive, understanding that a disease affects adults and children differently "can yield important insights into disease pathogenesis, informing management and the development of therapeutics."

Median time from illness onset to diagnoses was 2 days (range, 0 to 42). Cases accumulated rapidly in Hubei province from mid-January to early February and then tapered off.

More children in Hubei were infected than those in other provinces, although the virus quickly spread to neighboring regions. The authors noted that children were unlikely to have visited the Wuhan seafood market at the origin of the outbreak. "There were more children infected in the areas around Hubei province than areas farther away, except for Heilongjiang province," they wrote.

"As most of these children were likely to expose themselves to family members and/or other children with COVID-19, it clearly indicates person-to-person transmission."

Lower likelihood of infection, death

Because people with mild infections were unlikely to have been tested in Wuhan's overwhelmed health system, researchers in the Nature study used the prevalence of infected travelers on commercial flights before Jan 19 and on charter flights from Jan 29 to Feb 4 to and from the city to estimate the disease's true prevalence. They also used data from the first 425 confirmed cases to estimate the rate of disease spread.

They found that people younger than 30 years were 40% less likely (0.6 times as likely; 95% confidence interval, 0.3 to 1.1) to die of the infection than those 30 to 59 years. And those older than 59 were 5.1 (4.2 to 6.1) times more likely to die. The risk of having symptoms increased with age—roughly 4% a year in adults 30 to 60 years.

The overall risk of dying after having symptoms of the coronavirus was 1.4% (0.9% to 2.1%). Mean time from illness onset to death was 20 days (17 to 24; standard deviation [SD], 10 days [7 to 14]).

People younger than 30 also were 84% less likely to have a symptomatic infection (0.16 as likely; 0.15 to 0.17) than those 30 to 59 years, while those older than 59 years were 2.0 (1.95 to 2.08) times more likely to have a symptomatic infection. Children, however, were more likely to have a symptomatic infection than were those 20 to 29.

"There is a clear and considerable age dependency in symptomatic infection (susceptibility) and outcome (fatality) risks, by multiple folds in each case," the investigators said. "Unlike any previously reported pandemic or seasonal influenza, we find that risk of symptomatic infection also increases with age, although this may be in part due to preferential ascertainment of older and thus more severe cases."

Understanding the range of symptoms, disease severity, and prognosis is crucial in triage and diagnosis, "especially in settings without ready access to laboratory testing or when surge capacity has been exceeded," the authors wrote. It also helps clinicians choose the best treatment and health system leaders to manage supplies and staff appropriately.

On a larger scale, estimating both diagnosed and undiagnosed infections helps inform public health containment strategies in light of the severe social and economic disruptions they are likely to cause, the authors wrote.

Only 1 death in 171 cases

In the NEJM study, researchers used data from the China CDC to assess symptomatic and asymptomatic children who had contact with people with confirmed or possible infection at Wuhan's only designated COVID-19 pediatric hospital.

Of the 1,391 children tested from Jan 28 to Feb 26, 171 (12.3%) had confirmed infection, and 1 (0.6%) died of the disease. Median age of infected children was 6.7 years.

Many (41.5%) had fever, and cough and throat redness were also common. Twenty-seven (15.8%) had no symptoms or signs of pneumonia on x-ray, while 12 (7.0%) had signs on x-ray but no symptoms, for an asymptomatic rate of 22.8%. "Determination of the transmission potential of these asymptomatic patients is important for guiding the development of measures to control the ongoing pandemic," the authors wrote.

Low lymphocyte levels were found in six patients (3.5%), while x-ray showed areas of fluid buildup in both lungs in 32.7%.

Three patients, all with underlying medical conditions, needed intensive care and mechanical ventilation. The comorbidities included hydronephrosis (enlarged kidney due to retention of urine), leukemia (including receipt of chemotherapy), and intussusception (intestinal blockage).

The child with intussusception, a 10-month-old, had multi-organ failure and died 4 weeks after hospital admission. As of Mar 8, 21 patients were in stable condition in non–intensive care unit beds, and 149 had been released, according to the letter.

SARS-CoV-2 Infection in Children

https://www.nejm.org/doi/full/10.1056/NEJMc2005073?fbclid=IwAR2TOocmED1A5jy2lFbc01QkDlMviUo9u9o6lII6klsoGbvzp5NOUFzRuwE

As of March 10, 2020, the 2019 novel coronavirus (SARS-CoV-2) has been responsible for more than 110,000 infections and 4000 deaths worldwide, but data regarding the epidemiologic characteristics and clinical features of infected children are limited.1-3 A recent review of 72,314 cases by the Chinese Center for Disease Control and Prevention showed that less than 1% of the cases were in children younger than 10 years of age.2 In order to determine the spectrum of disease in children, we evaluated children infected with SARS-CoV-2 and treated at the Wuhan Children’s Hospital, the only center assigned by the central government for treating infected children under 16 years of age in Wuhan. Both symptomatic and asymptomatic children with known contact with persons having confirmed or suspected SARS-CoV-2 infection were evaluated. Nasopharyngeal or throat swabs were obtained for detection of SARS-CoV-2 RNA by established methods.4 The clinical outcomes were monitored up to March 8, 2020.

Table 1.

Epidemiologic Characteristics, Clinical Features, and Radiologic Findings of 171 Children with SARS-CoV-2 Infection.

Of the 1391 children assessed and tested from January 28 through February 26, 2020, a total of 171 (12.3%) were confirmed to have SARS-CoV-2 infection. Demographic data and clinical features are summarized in Table 1. (Details of the laboratory and radiologic findings are provided in the Supplementary Appendix, available with the full text of this letter at NEJM.org.) The median age of the infected children was 6.7 years. Fever was present in 41.5% of the children at any time during the illness. Other common signs and symptoms included cough and pharyngeal erythema. A total of 27 patients (15.8%) did not have any symptoms of infection or radiologic features of pneumonia. A total of 12 patients had radiologic features of pneumonia but did not have any symptoms of infection. During the course of hospitalization, 3 patients required intensive care support and invasive mechanical ventilation; all had coexisting conditions (hydronephrosis, leukemia [for which the patient was receiving maintenance chemotherapy], and intussusception). Lymphopenia (lymphocyte count, <1.2×109 per liter) was present in 6 patients (3.5%). The most common radiologic finding was bilateral ground-glass opacity (32.7%). As of March 8, 2020, there was one death. A 10-month-old child with intussusception had multiorgan failure and died 4 weeks after admission. A total of 21 patients were in stable condition in the general wards, and 149 have been discharged from the hospital.

This report describes a spectrum of illness from SARS-CoV-2 infection in children. In contrast with infected adults, most infected children appear to have a milder clinical course. Asymptomatic infections were not uncommon.2 Determination of the transmission potential of these asymptomatic patients is important for guiding the development of measures to control the ongoing pandemic.