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Officials in China have given permission for a Chinese drug maker¹ to begin commercial production of a human vaccine² against bird flu after clinical trials showed it was effective. Scientists worldwide are trying to find a way to prevent transmission of the virus.

在临床试验显示禽流感疫苗有效之后，中国官员已经批准大批量生产人用禽流感疫苗。世界各国的科学家正在寻找防止禽流感病毒传播的途径。

Officials from Sinovac Biotech, which jointly³ developed the vaccine with China's Center for Disease Control, say two clinical trials showed the vaccine worked.

北京科兴生物制品有限公司的负责人说，两期临床试验证明疫苗有效。该公司和中国疾病预防控制中心联合研制出这种人类使用的禽流感疫苗。

The development is a promising⁴ sign for scientists who have worked for years for develop a vaccine to protect humans from the H5N1 strain of bird flu. The virus has infected nearly 400 people and killed at least 238 worldwide, most of them in Asia.

这一进展对多年来为防止人类感染H5N1型禽流感病毒而努力研制疫苗的科学家来说是一个喜讯。在世界范围已经有近400人感染这种致命病毒，并导致至少238人死亡，其中大多数死亡病例发生在亚洲。

Experts worry that the H5N1 strain could cause a deadly flu pandemic in humans.

专家担心，H5N1型禽流感病毒有可能导致出现人之间传播的致命传染病。

So far, most human victims have caught the virus from sick poultry⁵. But there have been some cases of human-to-human exposure.

迄今为止，人类死亡病例大多是因为病人接触生病的家禽而感染禽流感病毒的，但是也出现了几例人与人之间感染的病例。

Malik Peiris teaches microbiology at Hong Kong University. He was among the scientists who first identified the virus when it appeared in the city 11 years ago, and was part of a team that provided the genetic⁶ map of the bird flu virus and its mutations.

马利克.佩利斯在香港大学教授微生物学，11年前香港爆发禽流感时，他是发现H5N1型禽流感病毒的首批科学家之一，并参与了解析禽流感病毒基因图以及基因变异的研究小组的工作。

"The concern of course is that if you give this virus enough time to keep on exposing the human population, sooner or later the virus might learn the trick of transmitting from human to human and then we would have a pandemic and actually quite a nasty pandemic at that," Peiris said.

佩利斯说：“人们担心的是，如果这种病毒有着足够的时间接触人体，那么它迟早能学会如何在人类之间传播，到那时我们将面临一场流行病的爆发，后果相当严重的。”

Peiris says it is crucial to find an vaccine now because there is a strong chance that the infection rate could grow rapidly. He says the history of H5N1 appears similar to that of Severe Acute Respiratory Syndrome⁷, which appeared in China in 2002, and spread around the world, killing⁸ nearly 800 people. In Hong Kong, 299 people died.

佩利斯说，目前极为关键的是要研制出疫苗，因为禽流感病毒的感染率极有可能很高。他说，H5N1型禽流感病毒的历史看起来跟萨斯病毒相似。2002年在中国爆发的萨斯病蔓延到世界范围，导致近800人丧生，香港有299人死于萨斯病。

"If you go back to the story of SARS, again it was quite a similar situation as we can see now in retrospect⁹, again it was a virus found in animals and animal markets in southern China and probably over a number of years it was repeatedly infecting humans," Peiris said. "But finally it did adapt and learn how to transmit from human to human and then it led to this global outbreak that we saw."

佩利斯说：“如果我们回顾一下萨斯病的历史，就可以看到一个相当雷同的现象。萨斯病毒也是在动物身上、在中国南方动物市场上发现的病毒。病毒在好几年间反复被人类感染上。这期间，萨斯病毒最终学会了适应人体，学会了如何在人类之间进行传播，最后导致了一场我们目睹的全球性萨斯病的爆发。”

Since the H5N1 flu reappeared in 2003, the virus has spread worldwide, and has led to the deaths of hundreds of millions of chickens, ducks and other birds. Indonesia has the highest human bird flu fatalities¹⁰, at 107 deaths, followed by Vietnam at 52.

自从H5N1型禽流感病毒2003年再此出现以来，已经在世界范围蔓延开来，导致千百万只鸡鸭和其他禽类的死亡和宰杀。印度尼西亚是人类感染禽流感死亡人数最多的国家，有107个死亡病例，其次是越南，有52人死亡。

Experts now consider the virus to be well entrenched¹¹ in Southeast Asia and unlikely to be eradicated¹² among poultry for years.

Vietnam also plans to start clinical trials for a human vaccine. A vaccine designed using a current strain of the virus might not offer full protection against other mutated strains in the future. But experts say developing vaccines¹³ now could at the very least shorten the time needed to make a more effective vaccine in the case of a pandemic.