人类征服艾滋病？

　　“联合疫苗”的成功率还不够高，而且其正式投产及广泛应用，仍然需要很长时间。

　　时至今日，癌症已有康复案例，而艾滋病仍是名副其实的绝症。一旦艾滋病检测结果呈阳性，就意味着患者与死神会面的日子不远矣。目前，艾滋病已经夺去了2500万人的生命，还有3300万人正在被艾滋病折磨着。

　　在过去30年里，全世界的科学家都在孜孜不倦地研发艾滋病疫苗。2009年9月24日，艾滋病疫苗研发领域终于第一次传出了好消息：美国和泰国研究人员共同宣布，双方合作研发的一种“联合疫苗”可以将人体感染艾滋病病毒的风险降低31.2%。虽然只有31.2%，但这却是人类首次获得具有免疫效果的艾滋病疫苗。

　　这种艾滋病疫苗采用了双疫苗策略，应用的两种疫苗分别是法国Aventis Pasteur公司生产的ALVAC和美国VaxGen公司生产的AIDSVAX。临床试验开始于2003年10月，为史上最大规模的艾滋疫苗试验——共花费了1.05亿美元。试验目的有二：一是检测疫苗对艾滋病毒的抵抗与预防能力，二是检测疫苗对已存在于血液中的艾滋病毒的杀伤能力。泰国的1.6万名年龄在18-30岁的志愿者接受了这项试验。试验前，其艾滋病病毒检测均为阴性，感染风险也与普通人群平均水平相当。一组实验者接受了6次 “联合疫苗”注射，另一组则只接受安慰剂注射。出于伦理道德考虑，试验组织者还给所有志愿者发放了免费的安全套，教给他们必要的性常识，并每3年对他们进行一次体检。结果显示，8197名接受疫苗注射的志愿者中，有51人感染了艾滋病病毒；而在安慰剂组的8198人中，则有74人感染——接受疫苗注射后，艾滋病感染率降低了31.2%。

　　不过，别忙着高兴。这种艾滋病疫苗试验只在泰国进行，只针对泰国常见的艾滋病毒类型，它对其他国家的常见艾滋病毒类型是否有效，还需要进一步研究。另外，当ALVAC和AIDSVAX这两种疫苗单独使用时，并不能起到任何明显的效果。ALVAC疫苗的原理是先让免疫系统准备好攻击艾滋病毒（它能够驱使人体产生白血球，杀死感染HIV的细胞）；而AIDSVAX是一种来自艾滋病毒外膜的蛋白质，可以刺激人体产生抗体，袭击血液中的病毒，进而促进免疫反应。但AIDSVAX的第一轮单独试验就宣告失败，而ALVAC的有效性则尚未得到证实。在“联合疫苗”中，这两种疫苗各起到什么作用，还有待进一步研究。有专家质疑，感染艾滋病人数差异可能只是“碰巧”。如果安慰剂组正好有更多人属于艾滋病高危人群，那么统计数据的意义就会大打折扣。

　　同时，该试验的另一个目的也已经宣告失败：“联合疫苗”并不能降低受感染者的病毒载量，也不能延缓艾滋病病毒的繁殖速度。在51名接种疫苗后感染艾滋病病毒的志愿者体内，病毒的繁殖程度与未接种者几乎没有区别。

　　目前，全世界平均每天净增艾滋病患者7500人，人们都对艾滋病疫苗研发寄予厚望。然而， “联合疫苗”31.2%的成功率，距离公认的绝对有效标准的50%成功率还有不小的差距，而且它的正式投产及广泛应用，仍然需要很长时间。世界卫生组织等机构纷纷出面表示，“联合疫苗”最大的功绩并不在于它是否真的有效，而在于它揭示了研究艾滋病疫苗成功的可能性是存在的。有学者则持另一种观点，认为不完美的艾滋疫苗，很可能导致许多人对艾滋病放松警惕、疏于防范。到目前为止，预防艾滋病最有效的措施，还是我们一直采用的那些。

　　要真正征服艾滋病，我们还有很长的路要走。

The human conquest of AIDS?

"Combination vaccine", the success rate is still not high enough, and its official production and wide application still needs a long time.

Today, cancer cases have been recovered, but is still worthy of the name of a terminally ill AIDS. Once the HIV test result is positive, it means that patients and the day is not far off the mark to meet death. Currently, AIDS has claimed 25 million lives, there are 33 million people are afflicted by AIDS.

In the past 30 years, scientists around the world have been tirelessly developing an AIDS vaccine. September 24, 2009, AIDS vaccine research and development for the first time at last came good news: the United States and Thailand, researchers announced that the cooperation developed a "vaccine" can the human body reduce the risk of HIV infection 31.2%. Although only 31.2%, but this is the first time with the immune effect of the human AIDS vaccine.

Such an AIDS vaccine using a dual vaccine strategies, application of the two vaccines were produced by Aventis Pasteur in France and the United States ALVAC produced by VaxGen's AIDSVAX. Clinical trial began in October 2003, for the history of the largest HIV vaccine trials - a total cost of 105 million. Test has two purposes: First, test the resistance to HIV vaccine and prevention capabilities, and second, testing the vaccine had been present in the blood of anti-HIV ability. Thailand 16000 volunteers aged 18-30 years accepted the test. Before the test, the HIV test were negative, with the general population the risk of infection is also very average. A group of experimenters received six times "combination vaccine" injection, another group received only placebo injections. For ethical considerations, testing all the volunteers returned to the organizers distributed free condoms, teach them the essential nature of knowledge, and every 3 years for them to conduct a medical examination. The results showed that 8197 vaccinated volunteers, 51 people infected with HIV; while in the placebo group of 8198 people, there are 74 people infected - after vaccination, AIDS infection rate reduced 31.2% .

However, not trouble yourself happy. This is only an AIDS vaccine trials in Thailand, only for the types of HIV strains prevalent in Thailand, its common in other countries the validity of the HIV type, but also requires further study. In addition, when ALVAC and AIDSVAX these two vaccines when used alone and can not play any significant results. ALVAC vaccine in principle is ready to let the immune system attacks the HIV virus (which can be driven by the human body produce white blood cells to kill HIV-infected cells); and AIDSVAX is an outer membrane protein from the HIV virus, can stimulate the body to produce antibodies, attack the virus in the blood, thus contributing to immune response. However, AIDSVAX the first round of tests on a separate failed, but the effectiveness of ALVAC has yet to be confirmed. In the "combined vaccine", this play what role the two vaccines, remains to be further studied. Some experts questioned the number of HIV-infected difference may just "happen." If the placebo group happen to have more and more people are at high risk of AIDS, then the meaning of statistical data will be compromised.

Meanwhile, another purpose of the trial has ended in failure: "combined vaccine" can not reduce their vulnerability to an infected person's viral load, can not slow down the reproduction rate of HIV. In the 51 vaccinated volunteers infected with HIV, the virus reproduction degree and non-vaccinated persons is almost no difference.

At present, the world's average daily net increase of 7,500 people living with AIDS, people have high hopes for AIDS vaccine development. However, the "combined vaccine" the success rate of 31.2% from the accepted standard of a totally effective and the success rate of 50% of the gap is not small, and its official production and extensive application still needs a long time. World Health Organization and other institutions have come forward, said, "combined vaccine" The biggest achievement is that it is not really effective, but because it reveals the AIDS vaccine research the possibility of success exists. Some scholars have held the alternative view that the HIV vaccine is not perfect, it could lead to AIDS, many people let down our guard, guard. So far, the most effective measures to prevent AIDS, or those that we have been used.

To truly conquer AIDS, we still have a long way to go.

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