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zoom RSS 豚インフルエンザワクチンは数ヶ月以上先に/米国医療事情

<<   作成日時 : 2009/05/01 00:48   >>

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 連邦当局によれば、豚インフルエンザからすべての米国人を保護するために必要なワクチン製造には1月、早くても11月末までかかると言う。世界的な需要を満たすには数年かかる
 数年前に考えられたよりは早くなったとはいえ、やはり間に合わない。この国の最も大きな問題は、何年もの努力にもかかわらず、インフルエンザワクチン製造に関してはまだ半世紀前のテクノロジーに頼っていることである。連邦当局はワクチン生産を鶏卵という古いテクノロジーではなく細胞でウイルスを成長させる方法に十億ドル以上の費用と年余の研究に費やしてきた。そして、新しいアプローチで数週で大量のワクチン製造を可能にするかもしれない多数の小さな会社がある。
 しかし、細胞ベースの生産は完全ではなく、新たなテクニックのいくつかが多くの専門家を満足させるには十分でない。当局はワクチン生産を保証するためにまだ、豚インフルエンザが十分な脅威であるかどうかについての決定をしていない。
 潜在的な問題として、豚インフルエンザワクチン製造が次季節のワクチン製造を妨害する可能性がある。ほとんどのメーカーは6月までに季節性ワクチン製造が生産し終わる予定なので、豚インフルエンザワクチン製造をその後始めれば最初の5000-8000万本は9月までに入手可能となる。米国人全てに2回分を提供するには1月までかかる。アジュバントと呼ばれる増強剤が追加されれば、必要な1回量で済み。11月までに摂取可能となる。
 米国には5年前2つのインフルエンザワクチン供給業者しかなかったが、現在は深刻な不足時にはよりずっと強い生産体制にある。現在は5社が供給しており、ワクチンに対して政府の補助金と高価格設定で製造業者も新たな投資を行っている。WHOや国際製薬会社連盟の研究では、新型鳥インフルエンザワクチンの世界的需要への対応には4年かかると試算された。豚インフルエンザワクチン製造も同様だろうと言う。要するに、十分なワクチンは迅速には用意できず、生産国にまず供給されるだろう
 鶏卵ではない細胞を用いたワクチン生産開発に13億ドルを政府は投入した。3億ドルを与えられたソルベーSolvayは、米国に製造プラントを建てるのは経済的に危険と決めた。Sanofi-Aventisはまた細胞培養生産を後回しにした。Novartisは細胞培養インフルエンザワクチン工場をノースカロライナ州のHolly Springsに建て、2010年-2011年に使用の用意ができているかもしれないと言う。連邦政府は建設費とワクチン購入保証に約5億ドルを提供している。
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Swine Flu Vaccine May Be Months Away, Experts Say
http://www.nytimes.com/2009/04/29/business/economy/29vaccine.html
By ANDREW POLLACK
Published: April 28, 2009
画像Federal officials said it would take until January, or late November at the earliest, to make enough vaccine to protect all Americans from a possible epidemic of swine flu.

And beyond the United States and a few other countries that also make vaccines, some experts said it could take years to produce enough swine flu vaccine to satisfy global demand.

Although production is much faster than would have been possible even a few years ago, it still may not be in time to avert death and illness if the virus starts spreading widely and becomes more virulent, some experts said.

In this country, the biggest problem is that despite years of effort, the country is still relying on half-century-old technology to make the flu vaccines.

Federal authorities have spent years and more than a billion dollars trying to shift vaccine production to a faster, more reliable method ― one that involves growing the vaccine viruses in vats of cells rather than in hen’s eggs, the old technology. And there are numerous small companies developing totally new approaches that might allow for the production of huge volumes of vaccines in a matter of weeks.

But the cell-based production is not quite ready, and some of the newer techniques are not proven enough to satisfy many experts.

“Those are all great technologies, but it isn’t going to happen in time,” said Dr. Greg Poland, head of the vaccine research program at the Mayo Clinic.

Federal officials have not yet made a decision on whether the swine flu is enough of a threat to warrant vaccine production. But they are taking the initial steps.

A potential problem is that producing swine flu vaccine might interfere with production of the seasonal flu vaccine for next winter.

“We would have to most likely make a compromise,” Andrin Oswald, chief executive of the vaccine division at the drug maker Novartis, said in an interview.

But Robin Robinson, who runs the emergency preparation research program for the federal Department of Health and Human Services, said most manufacturers would have finished producing the bulk of seasonal vaccine by June.

If production of the swine flu vaccine were to start right after that, the first 50 million to 80 million doses would be available by September, Dr. Robinson said.

A full 600 million doses, enough to provide the required two shots for each American, could be finished by January. If immune stimulants called adjuvants were added to the vaccine, that could reduce the dosage needed by each person, allowing enough doses to be ready by late November, he said.

The vaccine industry is in a much stronger position to respond now than it was five years ago, when the United States had only two flu vaccine suppliers and was hit by a severe shortage.

Now there are five suppliers to the domestic market. And the vaccine industry, once a backwater of the pharmaceutical industry, is attracting new investments, lured by government subsidies and higher prices for vaccines.

Still, a study done with the World Health Organization and the International Federation of Pharmaceutical Manufacturers and Associations estimated that it would probably take four years of production to satisfy fully global demand for a vaccine to protect against the bird flu strain that has concerned health authorities for the last few years.

Similar projections might apply to the swine flu vaccine, some experts say.

“The bottom line is there won’t be enough vaccine quickly enough and the vaccine will largely go to the countries that already produce the vaccine,” because countries will restrict exports in a pandemic, said Dr. David Fedson, an independent expert on pandemic preparedness.

The federal government is encouraging manufacturers to set up production in the United States, since all companies but one, Sanofi-Aventis, now import their flu vaccines.

The government also gave $1.3 billion, spread among several manufacturers, to develop ways of producing the vaccine in vats of animal cells rather than in eggs. Cell culture is less vulnerable to contamination and the process could save at least a few weeks.

The results so far have been mixed. Solvay, which was awarded the biggest federal grant, nearly $300 million, decided it was economically too risky to build a flu vaccine plant in the United States. (Most of the grant money had not yet left federal coffers and will not be lost, Dr. Robinson said.) Sanofi-Aventis has also put cell culture production on the back burner, Dr. Robinson said.

But Novartis is building a cell culture flu vaccine factory in Holly Springs, N.C., which might be ready for use in 2010 or 2011. The federal government is providing nearly $500 million in construction costs and guaranteed vaccine purchases.

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