WHO group envisions greater production of H1N1 vaccine（zt）

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Robert Roos  News Editor
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/ l5 B" s3 ~# y% U% f: }May 19, 2009 (CIDRAP News) – A new report from a World Health Organization (WHO) advisory group predicts that global production of vaccine for the novel H1N1 influenza virus could be as much as 4.9 billon doses a year, far higher than previous estimates.

5 U* V) l- a+ `7 P! J# d5 uThe report also says that it's "premature" to recommend starting mass production of an H1N1 vaccine now and predicts that if the recommendation is made, production could begin no sooner than mid-July. It gives no estimate of when the first doses would become available.

, R, i5 D( L2 v) {( B6 NThe four-page report is based on a May 14 teleconference of about 40 stakeholders, called the Ad Hoc Policy Advisory Working Group on Influenza A (H1N1) Vaccines. It was released late yesterday.

; N% K* _8 K- `" ]6 r, n5 L2 C3 TThe report says that vaccine makers are expected to produce about 480 million doses of seasonal flu vaccine for the northern hemisphere's 2008-09 flu season. About 350 million doses will be ready by June 30 and 430 million doses by Jul 31.
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The report continues, "It is estimated that up to 4.9 billion doses [of novel H1N1 vaccine] could be produced over a 12-month period after the initiation of full-scale production," if production yields are about the same as for seasonal flu vaccines and if "the most dose-sparing formulations" are used.

The estimate of 4.9 billion doses is far above the 1 billion to 2 billion doses mentioned by the WHO's Dr. Marie-Paul Kieny at a news briefing on May 6. She said that was based on an estimated global production capacity of about 900 million doses for seasonal vaccine.
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3 Y+ _  T* b- B9 ?0 ^/ r% P) LThe report does not explain what the 4.9-billion-dose estimate is based on, and WHO officials did not reply to a query about this today. But the mention of dose-sparing formulations is an apparent reference to adjuvants—immune-system stimulants that, when added to a vaccine, allow doses to be diluted, thus increasing supplies.

The working group also says that with total annual production of 4.9 billion doses, the United Nations (UN) could potentially have access to 400 million doses.

4 x- k/ y! T5 b: {. {/ ^9 J% s) MThe report says that a monovalent, or single-strain, vaccine is the preferred option for the H1N1 vaccine. There has been speculation about adding a novel H1N1 vaccine to the seasonal flu vaccine, which targets three flu strains, creating a four-strain vaccine that could protect against seasonal flu and the novel virus. But the report says this "would have significant regulatory implications," implying it would cause delays.

Timing considerations
) ?% M; \3 h& A5 O; L. R- g* T. |Concerning production timetables, the report says that candidate vaccine viruses (seed strains) will become available to vaccine makers at the end of this month—on the later end of previous estimates, which were sometime in the second half of May. But distribution of the seed strains may need to be delayed another week or two for testing in animals to make sure they are safe.
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, q4 o6 p* g5 e! ~; D9 V# F"Typically one to two additional months are needed by manufacturers after they receive vaccine viruses to isolate rapid growing strains to [achieve] maximum yield," the report adds. "Based on these considerations, the Working Group concluded that manufacturers would not be ready to switch to large-scale production before mid-July 2009."
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* \# p% _6 F2 cIt adds that moving to production too quickly could lead to using strains that don't grow very well in eggs, as happened with a 2004 Vietnam strain of the H5N1 virus that was used for vaccine production.

The report does not suggest when the first vaccine doses might be ready, but health officials have said that, from the time manufacturers receive vaccine seed strains, it will probably take 4 to 6 months to start producing an H1N1 vaccine in quantity. With the vaccine viruses going to manufacturers at the end of May, that suggests that the first doses could be ready in October.

Sanofi Pasteur, the largest flu vaccine supplier for the US market in recent years, expects to be able to produce its first doses of an H1N1 vaccine within 3 to 4 months after receiving the seed strains, a company spokeswoman said today.

6 S/ l* Z. i, ?/ y; z* w, W"Typically once we receive the seed virus, in a couple of weeks we can be ready to move to full-scale production, and in a couple of months—three to four—we believe we will have the first doses to provide to health authorities," Donna Cary, director of public relations, told CIDRAP News.

& u6 X5 W7 [. a2 _1 K/ S0 Y"We will have better information once we receive the seed virus and reagents and the government establishes the licensure process," she added.

& x2 V6 F* Z$ D% @& |9 {. f/ xGlaxoSmithKline, which also sells flu vaccine in the United States, will probably need 4 to 6 months to start providing vaccine after it receives the seed strains, company spokeswoman Sarah Alspach told CIDRAP News today. She noted that clinical trials will be necessary, and unpredictable hurdles could crop up.
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+ r1 t, p; D5 \  x8 mThe WHO report notes that many factors affecting H1N1 vaccine supplies remain unknown, including the optimal dose, the required number of doses, the required interval between doses, the interchangeability of different products, and the safety profile.

8 S  b. i$ k. Q) F# cOne safety issue will be the risk of Guillian-Barre syndrome, the paralytic condition that ultimately derailed the nationwide swine flu vaccination campaign in 1976, the report says. It recommends determining baseline rates of the syndrome in various populations before a pandemic vaccine is available, so that any later changes in its incidence can be detected.
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8 h0 l' s) |" ?+ Y3 JVow to help developing countries
In other developments today, WHO Director-General Margaret Chan said vaccine company executives who met with the agency today showed a "serious commitment" to helping provide H1N1 vaccines for developing countries, but she gave no specifics on what the companies might do.

5 @% Y: B4 ^% Q  OIn a press release, the WHO said it would work with the UN and other groups "to find innovative funding mechanisms to ensure that developing countries were not denied access to vaccines because of lack of means."
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Chan said she would meet with vaccine manufacturers individually to develop strategies to make vaccine supplies available to needy countries, according to the release.

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世卫专家组称甲型流感疫苗最快7月大规模生产（ZT）
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中广网北京5月20日消息

9 C: T0 y* d/ n% }　　世界卫生组织“战略咨询专家组（SAGE）”19日发布一份评估报告称，一旦甲型H1N1流感疫苗研制完毕开始大规模生产，预计全球年生产能力最大可达49亿剂。

　　“战略咨询专家组”报告说，一旦世卫组织正式建议开始大规模生产甲型H1N1流感疫苗，预计一年内全球最大产能可达49亿剂，其中联合国可获得4亿剂储备。

     该专家组称，用于生产甲型H1N1流感疫苗的候选病毒到5月底可准备完毕。接下来可能需要一到两个星期时间进行相关的动物实验，才能将病毒分发到各疫苗生产商。这些生产商通常还需要一到两个月分离快速生长病毒毒株以获取最大产量，才能真正开始疫苗生产。综合以上因素，专家组预计，最快要到今年7月中旬，全球疫苗生产商才能开始大规模生产甲型H1N1流感疫苗。
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3 H# Y( M9 p# Z7 ~7 ?3 \7 D　　报告说，目前临床血清测试表明，2007－2008年度或者2008－2009年度的季节性流感疫苗对于甲型H1N1流感并无免疫力，这就意味着注射季节性流感疫苗并不能为人们防范新型流感提供保护。
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3 J$ v  q9 a7 ~, f. i5 @0 g+ k　　对于正在研制中的甲型H1N1流感疫苗，一些具体的免疫学数据目前也尚未确定，比如提供免疫保护所需的疫苗剂数、隔多长时间注射第二剂等。专家组认为，鉴于人们对于甲型H1N1这一新型流感病毒完全没有免疫力，因此届时可能需要注射两剂疫苗才能达到较佳的保护效果。另外，有关疫苗的安全性也尚未确定，比如注射后出现格林－巴利综合征的风险有多大等，因此必须密切监测疫苗上市前后的安全性。
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  `( f2 m6 t( k　　报告说，目前流行病学分析表明，甲型H1N1流感病毒潜在的传播能力至少与季节性流感病毒相当，可以引发持续性的群体暴发。该专家组表示，将密切关注甲型H1N1流感疫情的动态，以便及时应对。 (来源：新华网)

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疫苗能不能够相对准确地预测病毒变异也是一个问题挖！

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* j, M9 q+ A  N! z& m9 _; v这都得拜托那些专家们了！