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zoom RSS インフルエンザワクチンの臨床試験は順調に進行/米国 新型インフルエンザワクチン

<<   作成日時 : 2009/08/27 19:50   >>

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 金曜日の連邦保健当局の発表では、新型ブタインフルエンザワクチンの現在までの治験で重大な副作用はなく、年末までに約2億本が製造できるだろうと言う。
 成人の臨床試験は8月7日に始まり、子どもは水曜日に始まった。安全性については心配ないという。成人での唯一の副作用が腫脹であったため子どもへの試験が開始された。妊婦への試験は来月初旬に始める予定だとCDCは言う。約4,500人で試験される。1回投与か2回かを決めるための資料にもなる。季節性インフルエンザでは、十分な免疫反応を得るために一度もインフルエンザにかかったことのないような子どもは2回接種が必要とされる。
 ウイルスが変わらない限りはアジュバントの追加はしない予定である。
 南半球では冬の初めにあたる6月に感染がピークとなりその後は鎮静し始めた。米国ではアラスカとメーンで広範囲に及んでいるが、「散発性的」である。アラスカには遅れて広まったのがその理由だろう。ウイルスは、現時点では、致死性の高いタイプに変異していない。タミフル耐性ウイルスがいくつかの国で発見されたが、広範囲に及ばなかった。金曜日、チリの2つの大きな商業用農場の七面鳥で新型インフルエンザが発見されたという報告があったが、致死性ではなかった。
 バトラー博士は、米国ではほとんどのインフルエンザが検査されないので、検査で立証されたブタインフルエンザ死者は522人であったが、実数は疑いなくより多いと言う。CDCの見積もりでは数百万人が感染したという。子どもと50才以下の成人が入院患者の75%、死者の60%を占めている。
 学校の新学期が始まり寒く乾燥した季節となるので感染が急増すると予想され、感染した学生は家に帰るよう勧告されるだろう。
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No Side Effects So Far in Trial of Swine Flu Shot
http://www.nytimes.com/2009/08/22/us/22flu.html
By DONALD G. McNEIL Jr.
Published: August 21, 2009

There have been no serious side effects from the first set of injections of the new swine flu vaccine, federal health officials said Friday in predicting that nearly 200 million doses could be produced by year’s end.

Clinical trials in adults began on Aug. 7, and those in children on Wednesday.

“There are no red flags regarding safety,” said Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, which is overseeing the trials.

Because the only side effects in adults were sore arms, which are typical of any flu shot, trials on children were able to begin, and those in pregnant women are expected to begin early next month, Dr. Fauci said in a telephone news conference with officials from the Food and Drug Administration and the Centers for Disease Control and Prevention.

The vaccine will be tested in about 4,500 people. That is far too few to pick up subtle side effects, but the virus strain in the vaccine is close enough to one strain in seasonal shots so that side effects are expected to be similar.

The trials will help officials decide whether to recommend one dose or two. Even with seasonal flu shots, young children who have never had the flu sometimes need two doses to get a “take” ― vaccinologist jargon for a protective immune response.

Unless the virus changes, health officials do not expect to recommend mixing in adjuvants. Adjuvants, usually oil-water emulsions or aluminum salts, boost the immune system but also often heighten unpleasant side effects.

Since it was first detected in April, the pandemic virus has not produced any nasty new surprises during its spread around the world, said Dr. Jay C. Butler, director of the H1N1 Vaccine Task Force at the C.D.C.

Flu activity in the Southern Hemisphere, which soared in June at the beginning of its winter, has begun to wane. In most of the United States, flu activity is “sporadic,” though it is widespread in Alaska and Maine; the reasons for this disparity are unknown, other than for Dr. Butler’s speculation that since swine flu arrived late in Alaska, it may still be peaking.

The virus has not crossbred with other flu viruses or mutated to produce proteins that could make it more lethal. And while some Tamiflu-resistant virus has been found in several countries, it has not become widespread.

Health officials said they were not particularly alarmed by reports Friday that the new flu had been found in turkeys on two large commercial farms in Chile, the first time it had been reported in birds.

“It’s widespread in humans, so who cares if it’s in turkeys?” Dr. Fauci said. “That’s a Department of Agriculture issue.”

Influenza viruses are most commonly found in birds, pigs and humans, though they can infect seals, dogs, horses, ferrets and many other animals.

The flu did not kill the turkeys; it was noticed only because their egg laying fell off and they drank less water. They will be quarantined and allowed to recover, Chilean agriculture officials said.

The H5N1 bird flu, by contrast, is lethal to poultry, and infected flocks are usually culled.

Although the possibility exists that the mild pandemic flu could swap genes with a lethal avian flu in bird hosts and then make the jump back to people, Dr. Fauci pointed out that the dangerous avian flu was circulating in Asia and Egypt, not in South America.

“You could dream up a variety of scenarios,” he said, “but we have enough H1N1 to worry about without worrying about turkeys.”

In the United States, there have been 522 swine flu deaths confirmed by lab tests, but the real number is undoubtedly higher, Dr. Butler said, because most flu cases are not tested.

Though it has been weeks since the C.D.C. raised its official estimate of swine flu cases, Dr. Butler acknowledged that millions of people had been infected. Children, teenagers and adults under 50 have accounted for about 75 percent of hospitalizations and 60 percent of deaths.

The agency expects cases to surge as soon as students return to school and as colder, drier fall weather sets in. Officials have urged schools to prepare, especially by keeping sick students out and making well students wash their hands frequently and cover coughs and sneezes. Universities have been urged to warn students to be ready to go home or to the house of a relative or friend if they fall ill.

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インフルエンザワクチンの臨床試験は順調に進行/米国 新型インフルエンザワクチン 医師の一分/BIGLOBEウェブリブログ
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