First AIDS vaccine tested did not protect, but gives scientific leads.The first "phase III" trial -- one large enough to determine whether a treatment works -- of an AIDS vaccine AIDS vaccine A hypothetical vaccine intended to either prevent HIV infection or ensure that those infected will not fall victim to AIDS; the most promising vaccine is that using a naked DNA plasmid, reported by Letwin et al in 20/10/00 Science; as of early 2001, in humans found that the vaccine (called AIDSVAX, produced by VaxGen in Brisbane, California) failed to protect people from HIV HIV (Human Immunodeficiency Virus), either of two closely related retroviruses that invade T-helper lymphocytes and are responsible for AIDS. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is responsible for the vast majority of AIDS in the United States. infection. But thousands of blood tests now being analyzed will likely provide important information for making better vaccines. Some of this work will be reported at the "HIV Vaccine HIV vaccine AIDS As of mid-2005, there is no viable anti-HIV vaccine. See AIDS. Development: Immunological and Biological Challenges" meeting beginning March 29 in Banff, Canada. Many scientists did not expect AIDSVAX to work, because this vaccine only produces antibodies against HIV and does not stimulate another branch of the immune system immune system Cells, cell products, organs, and structures of the body involved in the detection and destruction of foreign invaders, such as bacteria, viruses, and cancer cells. Immunity is based on the system's ability to launch a defense against such invaders. called cellular immunity. Recently, however, there has been renewed interest in antibodies -- partly because of growing knowledge about how to select the right antibodies, and also because cellular immunity alone may not prevent infection but only slow disease development. HIV vaccines might need to use both. The VaxGen report led to controversy because of suggestions that AIDS VAX (Virtual Address eXtension) A venerable family of 32-bit computers from HP (via Digital and Compaq) introduced in 1977 with the VAX-11/780. VAX models ranged from desktop units to mainframes all running the same VMS operating system, and VAXes could emulate PDP models might work partially in Blacks, or Asians. In Black volunteers, only 4 of 203 who received the vaccine later became infected with HIV, compared to 9 of 111 who received the placebo; in Asians the numbers were 2 of 20 vs. 2 of 53. There is a widespread consensus that no conclusions about human effectiveness can be drawn from such small numbers -- although more research is needed to look for possible racial differences, and this work has started. (This vaccine is not relevant to Africa because it was made specifically for the clade clade Cladus, subtype Genetics A branch of biological taxa or species that share features inherited from a common ancestor; a single phylogenetic group or line. See Inheritance, Species. B virus, which causes the AIDS epidemic in the U.S., Europe, and some other areas, but is not common in Africa, where AIDS is caused by clade C and other clades of HIV.) For more information on the science and controversy around the February 24 VaxGen report, see: * "Understanding the Results of the AIDSVAX Trial, by AVAC AVAC Automated Vacuum , the AIDS Vaccine Advocacy Coalition, http://www.avac.org/, or directly at: http://www.avac.org/pdf/UnderstandingAlDSVAX.pdf (capitalization does matter). * Articles by Jon Cohen in Science magazine, February 28, 2003 and March 7, 2003 (and any following issues). |
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