FDA批准首个四价流感疫苗

一种用于2岁~49岁人群预防季节性流感的疫苗——FluMist四价疫苗于2月29日获得美国食品和药物管理局批准。FluMist四价流感疫苗是第一种包含4种流感病毒株[2种甲型流感病毒株（H1N1,H3N2）和2种乙型流感病毒株]的疫苗。

9 L8 @; @! J: h5 j; T8 T（4-in-1 flu vaccine）
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与已经获批的FluMist（三价）一样，该四价疫苗中含有经过弱化的病毒株，并通过喷入鼻腔接种。引起人类疾病和死亡的流感病毒有两类：甲型流感和乙型流感病毒。每年，经FDA批准的疫苗中含有3种流感病毒株——2种甲型流感病毒株和1种乙型流感病毒株。在典型的流感季节期间，可能会流行2种不同的乙型流感病毒，或者三价流感疫苗所选择纳入的乙型流感病毒株可能并不是最终流行的致病病毒株。FluMist四价疫苗纳入了另一种乙型流感病毒株，这增加了充分预防流行性乙型流感毒株的可能性。
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"与其他任何人群相比，乙型流感病毒引起的疾病对儿童，特别是青少年和学龄儿童的影响面更大，FDA生物制品评价与研究中心主任、医学博士Karen Midthun说。"包含有最可能蔓延并引起流感季节疾病的4种病毒株的疫苗为辅助预防流感的努力提供了另一种选择。"

1 F3 N4 d( D" X- V5 ~- x2 _0 w接种疫苗是预防流感的最佳方法。流感季节不可预知，并且有可能会非常严重，甚至是致命的。在1976年~2007年间，美国与流感相关的死亡估计人数从3000人（估计低值）~490000人（估计高值）不等。
先前进行的关于FluMist三价疫苗配方的研究和3项涉及约4000名美国儿童及成人的新的临床研究支持FluMist四价疫苗的安全性和有效性。研究表明，FluMist四价疫苗与FluMist的免疫反应类似。 接种FluMist四价疫苗者与接种FluMist者所报告的不良反应类似。所报告的儿童和成年人中最常见的不良反应是均为流鼻涕或鼻塞，成人的最常见不良反应还有头痛和咽痛。

FluMist四价疫苗由马里兰州盖瑟斯堡市的MedImmune有限责任公司制造。

【附】FDA信息发布全文

FDA approves first quadrivalent vaccine to prevent seasonal influenza
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FluMist Quadrivalent, a vaccine to prevent seasonal influenza in people ages 2 years through 49 years, has been approved today by the U.S. Food and Drug Administration. FluMist Quadrivalent is the first influenza vaccine to contain four strains of the influenza virus, two influenza A strains and two influenza B strains.
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- h; [) P( \) O; g; S8 |% wLike the already approved FluMist (trivalent), the quadrivalent vaccine contains weakened forms of the virus strains and is administered as a spray into the nose.

There are two types of influenza viruses that cause illness and death in people: influenza A and B. Each year, the FDA-approved seasonal influenza vaccine includes three strains of influenza virus, two strains of influenza A and one of influenza B. During a typical influenza season, there may be two different influenza B strains circulating, or the B strain selected for inclusion in the trivalent influenza vaccine may not be the influenza B strain that eventually circulates causing illness. The inclusion of a second B strain in FluMist Quadrivalent increases the likelihood of adequate protection against circulating influenza B strains.

0 y; j  E% V6 x: R6 ]/ ]“Illness caused by Influenza B virus affects children, particularly young and school-aged, more than any other population,” said Karen Midthun, M.D., director of the FDA’s Center for Biologics Evaluation and Research. “A vaccine containing the four virus strains most likely to spread and cause illness during the influenza season offers an additional option to aid in influenza prevention efforts.”

Vaccination is the best method to prevent influenza. Influenza seasons are unpredictable and can be severe, even deadly. Between 1976 and 2007, estimates of seasonal influenza-associated deaths in the United States ranged from a low of about 3,000 to a high of about 49,000 people.

$ M0 ^  S/ ^/ D+ M; b2 b. G9 v9 z: JThe safety and effectiveness of FluMist Quadrivalent is supported by studies conducted previously for the FluMist trivalent formulation and three new clinical studies conducted in the United States involving about 4,000 children and adults. The studies demonstrated that the immune responses were similar between FluMist Quadrivalent and FluMist. Adverse reactions reported were similar among those receiving FluMist Quadrivalent and FluMist. The most commonly reported adverse reactions were runny or stuffy nose in both children and adults, and headache and sore throat in adults.

FluMist Quadrivalent is manufactured by MedImmune LLC of Gaithersburg, Md.