HIV vaccine: another failure
Clinical trials of the HIV vaccine have been discontinued
The second phase of clinical trials called HVTN 505 has been conducted since 2009 under the auspices of the American National Institute of Allergy and Infectious Diseases (National Institute of Allergy and Infectious Diseases).
Initially, 1,350 volunteers participated in the research, later their number grew to 2504 people. According to the conditions of the selection, which took place in 19 major US cities, HIV-negative men who are homosexuals or who have changed their gender were allowed to participate in the trial. The volunteers were divided into two groups: one of them received a placebo, the other received an HIV vaccine.
At the beginning of the study, participants were injected with DNA fragments containing the genetic material of a number of surface and internal HIV proteins and designed to trigger an immune system response. After 24 weeks, the volunteers received an injection of recombinant DNA vaccine. It is based on adenovirus 5, which carries the genetic material of HIV antigens of the three most common subtypes of the virus.
In an interim report, which was published on April 22, the Safety commission announced new cases of infection among volunteers who participated in the study for 28 weeks – enough time for an immune response to appear. 27 vaccinated volunteers and 21 people from the control group were infected. In addition, 14 infected from the first group and 9 from the control group were identified among those who participated in the trials for less than 28 weeks.
During clinical trials, scientists have not found confirmation that the vaccine reduces the viral load in HIV-infected people, which was one of the goals of its creation.
Scientists and HIV experts were alarmed and disappointed by the failure of vaccine trials. "Of course, we hoped that we would finally be able to get a vaccine that is at least somewhat effective," regrets Michael Saag, MD, from the University of Alabama. "The differences between the two groups of participants have no statistical significance and do not mean that the vaccine increases the risk of infection," Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition, is quoted as saying.
Trials of another HIV vaccine, invented in 2009 and first tested in Thailand, are still ongoing. In the first study conducted among heterosexuals, it was proved that this vaccine reduces the risk of infection with the immunodeficiency virus by 31.2 percent (compared with placebo).
Portal "Eternal youth" http://vechnayamolodost.ru26.04.2013