香港科学家为AIDS疫苗奋斗

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Experts working on vaccine to fight AIDS in China

HONG KONG (Reuters) - Scientists in Hong Kong and China are working on an AIDS vaccine to protect against three variants of HIV sweeping across south and west China, Hong Kong and Taiwan.

Chen Zhiwei, director of the new AIDS Institute in Hong Kong, said scientists have been using gene sequencing to track how HIV viruses in China are evolving, and their geographical spread.

Two closely-related HIV variants had spread through intravenous drug users (IDUs) from southwestern Yunnan province; one to as far as Xinjiang in the northwest, and the second to Guangdong in the south.

The third variant is in Yunnan and southern Guangxi province, which Chen said is passed mainly through heterosexual sex.

Chen, who worked alongside famous HIV/AIDS scientist David Ho in the U.S. before heading the Hong Kong institute, said collaborating scientists in the U.S. and China have designed a vaccine based on the two HIV variants spreading among IDUs and they hope to test it in animals by the end of this year.

\"If you want to make a vaccine, it is better to have a local strain as a target to work on,\" Chen said in an interview with Reuters.

Asked if the experimental vaccine may confer protection against the third variant that is transmitted chiefly through sex, Chen said: \"That's what we want to know. There is about 60-70 percent identity between the subtypes. If viruses are very closely related, chances of cross protection are better.\"

The HIV variants circulating in south and west China are very similar to those found in Myanmar, Vietnam, Cambodia, Thailand and India, as well as in Taiwan and Hong Kong, he said.

\"The epidemic in China has evolved over time. Previously, the major risk factors were IDUs and the tragic story of blood donation in central China. But after these people got infected, they passed it to their spouses, friends and these are in the general population,\" Chen said.

\"After 2006, heterosexual sex has been playing the major role in transmission of the virus. Infections have gone up in the general population and from mother to child.\"

The presence of these variants in Taiwan and Hong Kong also could be a tell-tale sign of the traveling routes of drug users in the region, Chen said.

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The AIDS Institute hopes to help set up HIV screening centers in China, which is estimated to have about 700,000 people living with HIV/AIDS, up from an earlier estimate of 650,000.

Chen also spoke about hundreds of thousands of HIV/AIDS patients in central China, who contracted the virus in the 1990s from unsanitary blood donations.

Despite free antiretroviral drugs provided by the government, some 30 percent of these patients have developed full-blown AIDS - which Chen attributed to drug resistance.

Antiretroviral drugs help keep the HIV virus in check and can prevent the progression to AIDS. But regimens can be complicated and sufferers can easily develop drug resistance if they miss doses - meaning they will then have to resort to stronger, more expensive, and in China, often unavailable drugs.

http://www.reuters.com/article/healthNews/idUST2363520080121



香港（路透社）——香港和中国大陆的科学家正在共同研究针对3种广泛分布在大陆、香港、台湾的基因型的HIV病毒的疫苗。

Chen Zhiwei（香港艾滋病研究中心主任）说：“研究者们一直在使用基因序列追踪广泛分布于中国的HIV病毒的基因型以及其地理分布。”

其中的两种关系十分密切的基因型是从云南的静脉注射吸毒者开始传播的，一种传播地远达新疆，一种传播到了广东。
第三种基因型主要分布在云南和广西，主要是通过异性间的性行为传播的。
Chen Zhiwei（曾经在著名的美国HIV/AIDS scientist David Ho工作过）说：“中美两国的科学家已经合作研制出针对在吸毒者中传播的两种基因型的HIV的疫苗，预计今年年底将会进入动物实验阶段。”

“要先研制出疫苗，最好将一个突破点作为目标。”他在接受路透社的采访时说。

当被问及这种疫苗是否也对于第三种通过异性间性行为传播的基因型有效时，他说：“这也是我们想要知道的。这些基因型之间有60%~70%的相似度，如果它们之间的联系性越高，则出现交叉保护的可能性则越大。”

“这种在中国的西南部流行的基因型与那些再缅甸、越南、柬埔寨、泰国、印度、香港、台湾流行的基因型有很多相似之处。”

“艾滋病在中国的流行日趋扩大化。最开始，发病人群主要是静脉吸毒者以及那些可怜的靠卖血为生的中部地区人民。但当他们被感染后，病毒则通过他们传递给配偶、朋友，现在，这些人已经成为了携带病毒的主要群体。”

“从2006年开始，异性间的性行为已经成了HIV病毒传播的主要方式。在大众群体中的被传染者人数正在增加，并且正在从母亲传递给婴儿。”

“这些在台湾、香港出现的这3种基因型同时也为追踪这些吸毒者的迁移路线提供了线索。”