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zoom RSS ブタインフルエンザによる子どもの死亡は神経疾患を持つ年長児に多い/CDC 新型インフルエンザ

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 ブタインフルエンザによる死亡が乳幼児より学童・年長児に多い/CDC
画像 米国における小児のブタインフルエンザによる死亡についての詳細な研究発表がされ、通常の季節性インフルエンザと異なり乳幼児より学童の犠牲者が多いという。木曜日のCDCの発表では、少なくとも40人の子どもが死亡し、ブタインフルエンザによる死者の1/13を占めた。2/3はハイリスクな健康問題を抱えていた。新型インフルエンザが通常の季節性インフルエンザより子どもに危険性が高いかどうかははっきりしないが、予備的な分析ではいくつかの点で重要な違いがある。
1.通常インフルエンザで死亡する子どもの半数以上は4才以下であるが、ブタインフルエンザで死亡した子どもの80%以上は5-17才であった。学校やサマーキャンプなど多くの人と接する時間が多いことによる可能性はある。
2.ブタインフルエンザで死亡した子どもの約2/3はてんかん・脳性麻痺・その他の神経発達的な問題を持っていた。前のインフルエンザシーズンに死亡した子どものではそうした条件を持っていたのは1/3だけだった。
3.ブタインフルエンザとともに他の細菌が大きな危険要因となり、健康な子どもの死因に大きな役割を果たしている。
 4月以来米国では100万人以上が感染し、8,800人以上が入院し、550人以上の死亡が確認された。CDCによれば、新型インフルエンザは、高齢者に危険で毎年約36,000人が死亡する季節性インフルエンザより悪いことを意味していないという。
 しかし、CDCのトーマス・フリーデン長官は、何人かの科学者が恐れていたが、ウイルスがより致死性が高くなるように変異している徴候は全然ないと言う。
 毎年50〜100人の子供は季節性インフルエンザで死亡する。しかし、ブタインフルエンザによる子どもの死亡が季節性インフルエンザより高いかどうかを説明することは難しい。CDCは詳しくブタインフルエンザによる死亡例を検討しており、今までの季節性インフルエンザでは行っていなかったためデータを直接比較検討できない。
 新たな報告は8月8日までに477例の確認されたブタインフルエンザによる死亡例を検討したもので、36人が子どもであった。4才以下はわずか約20%であり異常である。季節性インフルエンザでは免疫系が未熟で気道が狭く気道感染に弱い乳幼児の死亡が50%以上を占める。
 死亡した子どもの3分の2はハイリスクの疾患を持っていた。ほとんどすべては、精神発達遅滞、脳性麻痺、てんかん、その他のけいれん性疾患を含めて、神経系と関連した病気にかかっていた。何年も前から、専門家は、神経発達的な症状を持つ子どもがインフルエンザによるの重大な合併症をおこすより高いリスクを持つと認めていた。
 ブタインフルエンザにかかる前には健康であった10人の子どものうち、8人はインフルエンザとともに細菌性肺炎などの細菌感染を起こしていた。
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CDC Study: Swine Flu Deaths Higher in Older Kids
CDC study: Swine flu deaths are more common in school-age children than in babies or toddlers
http://abcnews.go.com/Health/SwineFlu/WireStory?id=8482023
By MIKE STOBBE AP Medical Writer
ATLANTA September 3, 2009 (AP)
The Associated Press

画像Swine flu deaths more common in older children, says 1st CDC study of virus' pediatric toll
About one in 13 U.S. swine flu deaths have been children and most of the kids have been of school age, the federal government said Thursday in its first study of the new flu's youngest victims. Collapse
(Justin Sullivan/Getty Images)

The first detailed study of U.S. children killed by swine flu found the outbreak differs from ordinary flu in at least one puzzling respect: It appears to be taking a higher toll on school-age youngsters than on babies and toddlers.

At least 40 children have died, accounting for about one in 13 U.S. swine flu deaths, scientists with the Centers for Disease Control and Prevention said Thursday. Two-thirds of those already had high-risk health problems, confirming what officials have been saying about who is most vulnerable to swine flu.

It is not clear whether the new virus is more dangerous than ordinary seasonal flu for kids, though some health officials suspect it is. But the analysis shows some preliminary and important differences:

― Normally, half or more of the children who die of the flu are 4 and under. But more than 80 percent of the kids who died with swine flu were 5 through 17. Dr. Beth Bell, a CDC epidemiologist, said that may be because older children spend time at school and summer camp, exposed to more people than younger children kept at home.

― Almost two-thirds of the children who died with swine flu had epilepsy, cerebral palsy or other neurodevelopmental conditions. In a previous flu season, only a third of the children who died had those conditions.

― Other germs, working with swine flu in a one-two punch, were a big danger. A bacterial infection on top of the flu virus played a role in most of the deaths of otherwise healthy children.

Swine flu was first identified in April and is now responsible for almost all flu cases in the United States. It has caused more than 1 million illnesses so far, though most were mild and not reported, the CDC estimates. More than 550 lab-confirmed deaths and 8,800 hospitalizations have been reported.

Those statistics don't mean the new flu is worse than seasonal flu, which is particularly lethal to the elderly and plays a role in an estimated 36,000 deaths each year, the CDC says.

But swine flu is causing more suffering in children and young adults than is customary, and a lot of parents are worried. Some emergency room doctors say they are seeing a lot of mildly ill children brought in by parents fearful that it is a swine flu case that will turn worse.

Right now, cases are most common in the Southeast, possibly because schools are already in session, providing more opportunity for infections to spread, CDC officials said.

However, there are no signs that the virus is mutating to become more deadly, as some scientists feared, CDC Director Thomas Frieden said.

Each year 50 to 100 children die of seasonal flu. But it's hard to say whether children account for a higher proportion of deaths from swine flu than they do from seasonal flu. The CDC doesn't monitor seasonal flu deaths as closely as it does swine flu, and has no comprehensive count of each year's flu deaths to enable such a comparison.

The new report focuses on 477 lab-confirmed swine flu deaths reported through Aug. 8. Thirty-six during that period were children.

Only about 20 percent of those children were 4 or younger. That's unusual. Often, 50 percent or more of seasonal flu deaths are babies or toddlers, who have less mature immune systems and smaller airways, putting them in more danger from respiratory infections.

Two-thirds of the children who died had high-risk medical conditions. Nearly all of them had an illness related to the nervous system, including mental retardation, cerebral palsy, epilepsy and other seizure disorders.

Years ago experts recognized that children with neurodevelopmental conditions run a higher risk of serious complications from the flu. But the proportion of swine flu victims with that kind of underlying condition is high compared to a previous flu season, CDC officials said.

It's not clear how significant that finding is, because many of the children had other medical problems besides the neurological conditions that had weakened their bodies, CDC officials said.

Of 10 children who were healthy before they got swine flu, eight had a bacterial infection such as bacterial pneumonia along with the flu.

―――
On the Net:
CDC report: http://www.cdc.gov/mmwr

Copyright 2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
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September 4, 2009 / Vol. 58 / No. 34
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5834a1.htm

Surveillance for Pediatric Deaths Associated with 2009 Pandemic Influenza A (H1N1) Virus Infection
United States, April-August 2009


Children aged <5 years or with certain chronic medical conditions are at increased risk for complications and death from influenza (1--3). Because of this increased risk, the Advisory Committee on Immunization Practices (ACIP) has prioritized influenza prevention and treatment for children aged <5 years and for those with certain chronic medical and immunosuppressive conditions (4,5). CDC monitors child influenza deaths through its influenza-associated pediatric mortality reporting system. As of August 8, 2009, CDC had received reports of 477 deaths associated with 2009 pandemic influenza A (H1N1) in the United States, including 36 deaths among children aged <18 years. To characterize these cases, CDC analyzed data from April to August 2009. The results of that analysis indicated that, of 36 children who died, seven (19%) were aged <5 years, and 24 (67%) had one or more of the high-risk medical conditions. Twenty-two (92%) of the 24 children with high-risk medical conditions had neurodevelopmental conditions. Among 23 children with culture or pathology results reported, laboratory-confirmed bacterial coinfections were identified in 10 (43%), including all six children who 1) were aged ≥5 years, 2) had no recognized high-risk condition, and 3) had culture or pathology results reported. Early diagnosis of influenza can enable prompt initiation of antiviral therapy for children who are at greater risk or severely ill. Clinicians also should be aware of the potential for severe bacterial coinfections among children diagnosed with influenza and treat accordingly. All children aged ≥6 months and caregivers of children aged <6 months should receive influenza A (H1N1) 2009 monovalent vaccine when available (6).

Influenza-associated pediatric deaths have been nationally notifiable since October 2004. The CDC case reporting system defines an influenza-associated pediatric death as a death in a person aged <18 years with an illness clinically compatible with influenza and whose influenza is laboratory confirmed. State and local health departments report influenza-associated pediatric deaths using a standardized case report form that collects information on demographics, dates of illness onset and death, location of death, chronic medical conditions, influenza testing, bacteria or fungi cultured from sterile and nonsterile sites, and medical care received during the influenza illness. The case report form provides a list of chronic medical conditions that have been associated previously with an increased risk for complications from seasonal influenza and space to describe additional chronic medical conditions not listed on the form. Results of pathology testing conducted at CDC also are included. Medical records, medical examiner reports, and death certificates were not reviewed.

This case series included data reported to CDC on all deaths associated with laboratory-confirmed 2009 pandemic influenza A (H1N1) virus infection occurring in persons aged <18 years through August 8, 2009. Laboratory confirmation was defined as a positive test for 2009 pandemic influenza A (H1N1) virus by reverse transcription--polymerase chain reaction (RT-PCR). CDC requested supplementary information from state and local health departments on antiviral treatment and chronic medical conditions for deaths associated with 2009 pandemic influenza A (H1N1) virus infection. For this case series, invasive bacterial coinfection was defined as laboratory detection of a bacterial pathogen in a specimen from a normally sterile site or a postmortem lung biopsy. Children were considered at high risk if they were aged <5 years or had one of the medical conditions recognized to increase the risk for influenza-related complications,* based on a review of the available medical data by a developmental pediatrician.

Thirty-six pediatric deaths associated with 2009 pandemic influenza A (H1N1) infection were reported from 15 state and local health authorities† through August 8 (Table 1).§ Illness onsets occurred during May 9--July 20, and deaths occurred during May 15--July 28. Six deaths occurred in May, 25 deaths in June, and five deaths in July. Median age of the patients was 9 years (range: 2 months--17 years); 50% were male, 42% were non-Hispanic white, and 33% were Hispanic (Table 2). Seven (19%) of the 36 children were aged <5 years (five were aged <2 years), and 24 (67%) had at least one high-risk medical condition, including three children aged <5 years. Among the 24 children with high-risk medical conditions, 22 (92%) had neurodevelopmental conditions (e.g., developmental delay or cerebral palsy). Of these 22 children, 13 (59%) had more than one neurodevelopmental diagnosis, and nine (41%) had neurodevelopmental and chronic pulmonary conditions. Eight (22%) of the 36 children were aged ≥5 years with no reported high-risk conditions. Two of these eight children were reported as obese; however, height and weight measurements were not reported.

Duration of illness before death in the 36 cases ranged from 1 day to 28 days (median: 6 days). Among 31 children for whom antiviral treatment data were available, 19 (61%) received antiviral treatment, and four of those received treatment within 2 days of illness onset. Of 25 children for whom information was available, 13 (52%) had received at least 1 dose of the 2008--09 seasonal influenza vaccine, including 11 children with high-risk medical conditions. Of the 23 children with culture or pathology results reported, 10 (43%) had a laboratory-confirmed bacterial coinfection, including Staphylococcus aureus (five, including three methicillin-resistant S. aureus), Streptococcus pneumoniae (three), Streptococcus pyogenes (one), and Streptococcus constellatus (one). Among the eight children aged ≥5 years who did not have a high-risk medical condition, six had a laboratory-confirmed invasive bacterial coinfection, including four with S. aureus; the other two children either had no specimens collected or information regarding bacterial coinfection was unavailable. Among the seven children aged <5 years who died, two had a laboratory-confirmed bacterial coinfection; neither child had a high-risk medical condition.

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ブタインフルエンザによる子どもの死亡は神経疾患を持つ年長児に多い/CDC 新型インフルエンザ 医師の一分/BIGLOBEウェブリブログ
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