本帖最後由 lsc0019 於 2009-5-24 20:49 編輯
作者：Martha Kerr
出處：WebMD醫學新聞
May 7, 2009(巴爾的摩) — 輕微早產的嬰兒，即使是那些幾乎將近週產者，嚴重呼吸道融合病毒(RSV)感染的風險仍然很高，需要在醫療上多加留意，有些甚至需要住院。
根據發表於小兒科協會2009年會中的研究，雖然極早產(懷孕週數<32週)是嚴重RSV感染的強烈風險因素，且有高發病率與死亡率，但懷孕37週左右的輕微早產也會增加嚴重RSV感染風險。
由資深研究科學家、Gabriel Escobar醫師領導的加州奧克蘭Kaiser Permanente產前研究小組，針對1996至2002年出院之懷孕週數至少33週的117,060名嬰兒進行回溯世代研究。
懷孕週數33至36週的嬰兒有6.32%在產後使用氧氣供應，37週以上的小孩有1.63%使用；懷孕週數33至36週的嬰兒有9.92%使用輔助呼吸裝置，37週以上的小孩有0.86%使用。
出生後第一年發生需治療之RSV感染的校正風險比(AHR)：
* 男性為1.33 (95% 信心區間[CI]為1.21 - 1.45)；
* 胎齡小者為1.36 (95% CI，0.99 - 1.85)；
* 出生後到出院前使用氧氣補充者為1.61 (95% CI，1.26 - 2.06)；
* 使用輔助呼吸裝置者為1.51 (95% CI，1.14 - 1.99)；
* RSV季節出院者為1.10(95% CI，1.00 - 1.21)。
相較於胎齡38至40週的新生兒，這些在38週前出生者的RSV風險顯著較高，AHR從37週的1.35 (95% CI，1.14 - 1.59)到33週的1.85 (95% CI，1.26 - 2.70)。
過產期出生嬰兒的RSV風險比足月嬰兒更低，AHR為0.83 (95% CI，0.73 - 0.95)；Escobar醫師表示，隨著胎齡減少，風險呈線性關係增加。
Escobar醫師在Medscape Pediatrics的訪問中表示，還不瞭解為什麼輕微早產、只早產2至3週的嬰兒有這麼高的嚴重RSV感染風險。
他認為，RSV是常見的。到了3歲時，幾乎有10%的小孩呈現抗體陽性。它通常像輕微的類似感冒症狀，但是我們現在討論的是有顯著病狀的嚴重RSV。
還不瞭解為什麼輕微早產也有嚴重病症；可能是肺部仍未完全成熟，或者免疫系統有其他不全之處。
Escobar醫師警告，病毒本身也未被充分瞭解，所以沒有RSV疫苗；目前僅限於在過度早產嬰兒使用pavilizumab進行預防，但是還未被核准用於輕微早產時。
安大略省McMaster大學、McMaster兒童醫院的Bosco Paes醫師領導的研究團隊，正在發展一項RSV登記方法，以呈現發生率和盛行率，藉以評估在2歲前RSV感染之治療的利用率。
在2005至2008年的RSV季節(11月至4月間)，中到高風險RSV的嬰兒每月接受palivizumab，迄今共有430名嬰兒接受palivizumab。
整體來說，78名(18.1%)嬰兒接受完整四劑的palivizumab。27名高風險嬰兒全部都接受完整的palivizumab；少部份低風險嬰兒接受較少次的單株抗體。
Paes醫師向Medscape Pediatrics表示，風險評分工具是不錯的使用者善用型工具，可以對33至35週胎齡的中到高風險嬰兒提供明確的RSV預防指引。
他指出，這個評分工具有成本效益，被視為RSV感染低風險的33至35週胎齡世代中，大部份(81.9%)避免預防措施，減少大多數有風險嬰兒的住院率。
Escobar醫師向Medscape Pediatrics表示，我堅信登記制度。我們在Kaiser Permanente開始執行。我對於早期的嚴重RSV感染是否代表後來哮喘與氣喘，特別感到興趣。
Paes醫師表示，加拿大的登記制度已經顯示出RSV統計資料的一些變化，住院發生率減少；這可能是因為pavilizumab使用增加，此藥在加拿大的使用比美國更廣泛。
製造pavilizumab的MedImmune藥廠資助Kaiser Permanente研究，Escobar醫師強調他沒有接受該公司的任何資金。Paes醫師宣告沒有相關財務關係。
小兒科協會(PAS)2009年會：摘要5418.6。發表於2009年5月3日。
PAS 2009: Even Mild Prematurity Increases Risk for Severe RSV Infection
By Martha Kerr
Medscape Medical News
May 7, 2009 (Baltimore, Maryland) — Mildly premature infants, even those who are nearly full term, are still at high risk for serious respiratory syncytial virus (RSV) infections that require medical attention, including hospitalization in some cases.
Although extreme prematurity (gestational age <32 weeks) is a strong risk factor for serious RSV infection and has a high incidence of significant morbidity and mortality, mild prematurity, with a gestational age of around 37 weeks, also increases risk for serious RSV infection, according to research presented here at the Pediatric Academic Societies 2009 Annual Meeting.
A team at Kaiser Permanente's Division of Perinatal Research in Oakland, California, led by senior research scientist Gabriel Escobar, MD, conducted a retrospective cohort study of 117,060 infants with a gestational age of at least 33 weeks discharged home between 1996 and 2002.
Supplemental oxygen use after delivery was 6.32% among infants from 33 to 36 weeks of gestation and 1.63% among those at 37 weeks of gestation and older. Assisted ventilation was used in 9.92% of infants between 33 and 36 weeks of gestation and 0.86% among those 37 weeks of gestation and older.
Adjusted hazard ratios (AHR) for "medically attended" RSV infection during the first year of life were:
1.33 (95% confidence interval [CI],1.21 - 1.45) for male sex;
1.36 (95% CI, 0.99 - 1.85) for small for gestational age;
1.61 (95% CI, 1.26 - 2.06) for supplemental oxygen use between birth and discharge;
1.51 (95% CI, 1.14 - 1.99) for assisted ventilation;
1.10 (95% CI, 1.00 - 1.21) for discharge during the RSV season.
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Compared with neonates from 38 to 40 weeks of gestation, those born before 38 weeks of gestation had a significantly higher risk for RSV, with AHR ranging from 1.35 (95% CI,1.14 - 1.59) for those born at 37 weeks, to 1.85 (95% CI, 1.26 - 2.70) for those born at 33 weeks.
Infants born postmature had a lower risk for RSV infection than full-term infants, with an AHR of 0.83 (95% CI, 0.73 - 0.95). "There was a linear increase in risk with decreasing gestational age," Dr. Escobar said.
"It is not understood why even mildly premature infants — approximately 2 to 3 weeks premature — have such a high risk of serious RSV infection," Dr. Escobar said in an interview with Medscape Pediatrics.
"RSV is ubiquitous. Nearly 10% of children are antibody-positive by age 3," he commented. "It usually manifests with mild cold-like symptoms?.?.?. but we're talking about serious RSV with significant morbidity."
"Why it is a serious illness even in mild prematurity is not well understood. It could be that the lungs are still not fully matured, or it may be that some other aspect of the immune system is compromised."
"The virus itself is not well understood, and that's why there is no RSV vaccine. Prevention is limited to the extremely premature infant, with pavilizumab, but it is not approved for use in mild prematurity," Dr. Escobar cautioned.
Canadian researchers, led by Bosco Paes, MD, from McMaster Children's Hospital, McMaster University in Hamilton, Ontario, are developing an RSV registry to document the incidence and prevalence rates and to evaluate utilization rates for the treatment of RSV infection during the first 2 years of life.
Infants at moderate to high risk for RSV received palivizumab at monthly intervals between November and April during the 2005 to 2008 RSV seasons. A total of 430 infants have received pavilizumab so far.
In all, 78 infants (18.1%) received the full 4-dose course of palivizumab. All 27 high-risk infants received full-course palivizumab; smaller percentages of the lower-risk infants received fewer doses of the monoclonal antibody.
"The Risk-Scoring Tool is a valuable user-friendly instrument to guide judicious RSV prophylaxis for moderate- to high-risk infants between 33 and 35 weeks of gestation," Dr. Paes told Medscape Pediatrics.
He added that the scoring tool "is cost-effective, reducing hospitalization in infants who are most 'at-risk' while avoiding prophylaxis in a large segment (81.9%) of this [33 to 35 weeks' gestation] cohort, who are considered low risk for RSV infection."
"I am a firm believer in registries," Dr. Escobar told Medscape Pediatrics. "We are starting to do this at Kaiser Permanente. I am particularly interested in seeing if severe RSV infection early in life predisposes a child to wheezing and asthma later in childhood."
Dr. Paes said that the Canadian registry is already showing a change in the demographics of RSV, with a decreasing incidence of hospitalization. "This could be due to the increasing use of pavilizumab, which is used more widely in Canada than in the [United States]."
The Kaiser Permanente study was funded by MedImmune, manufacturers of pavilizumab, but Dr. Escobar stressed that he receives no funding from the company of any kind. Dr. Paes has disclosed no relevant financial relationships.
Pediatric Academic Societies (PAS) 2009 Annual Meeting: Abstract 5418.6. Presented May 3, 2009. |
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