|problem with vaccine
Aug 12, 2008
vaccines for the flu don't make you not get the flu, they make your body fight it off when it comes. So, why do they consider it a failure of the Merck trials that it seemed to make the patient for susceptible to getting hiv? it scientfically jives that it SHOULD make them more suceptible, but once they get it, they're body will fight it off.
Since many doctors consider it a death sentence, people will never be injected with a weak strain of hiv in hopes of fighting it off, however, thats exactly what needs to happen for a successful vaccine. thoughts?
| Response from Dr. Frascino
My thoughts? OK. My basic thought is that you don't understand the details and complexities of vaccine immunology or HIV pathophysiology.
A vaccine teaches the immune system how to protect itself against a disease-causing germ, such as a virus or bacteria. Vaccines are one of the world's most effective public health tools. Effective vaccines against polio, measles, mumps, rubella and other disease have helped to dramatically decrease the incidence of these diseases in many parts of the world. The smallpox vaccine led to the elimination of that disease worldwide. Creating a vaccine for HIV has proven to be an extremely difficult challenge, as HIV is a retrovirus that integrates itself into the DNA of the host it infects. Despite more than 30 clinical trials of experimental AIDS vaccines in 25 countries around the world, we are still a long way off form developing an effective preventative or therapeutic vaccine. Recently, a large vaccine trial (STEP trial) was halted when the interim review showed the vaccine had no efficacy. A companion study in South Africa was also stopped. At this point, it's "back to the drawing board" for vaccine research. I post below some information related to our efforts to develope an effective HIV vaccine from Tony Fauci, M.D., the head of the National Institute of Allergy and Infectious Diseases. Stay tuned. We'll keep you posted on the vaccine story. At this point, it's safe to say we do not have a preventative or therapeutic HIV vaccine even on the distant horizon.
Statement of Anthony S. Fauci, M.D., on HIV Vaccine Awareness Day
May 18, 2008
Anthony S. Fauci, M.D., NIAID Director
Twenty-five years ago this month, researchers reported the isolation of the virus that causes AIDS. Since then, over 60 million people have been infected with HIV -- an estimated 2.5 million in 2007 alone -- numbers that remind us that the development of an HIV vaccine is an urgent humanitarian imperative. This year's HIV Vaccine Awareness Day provides us with an opportunity to renew and strengthen our commitment here at the National Institutes of Health (NIH) to finding a safe and effective HIV vaccine that will slow, and hopefully one day end, the HIV/AIDS pandemic.
The past year was a disappointing one in the search for a safe and effective HIV vaccine. The scientific concept tested in the HIV vaccine study known as the STEP trial was considered to have great promise; however, the vaccine did not have the desired beneficial effect. Although the finding was disappointing, it was not unusual given the nature of science and vaccine development. Historically, it has taken decades to find effective vaccines to combat infectious diseases. In the 89 years it took to create an effective pertussis vaccine and the 42 years it took to develop an effective measles vaccine, researchers experienced numerous setbacks and disappointments before reaching success; yet they persevered. Finding a safe and effective HIV vaccine demands an equally intense resolve.
Last year, 2.1 million people died as a result of AIDS, including 330,000 children under the age of 15. Today, 33.3 million people are living with HIV infection. Although the problem is most severe in sub-Saharan Africa, the United States also has been hard-hit: more than 565,000 people in this country have died of AIDS and an estimated 1.1 million are living with HIV infection. African-Americans and Hispanics shoulder the greatest burden, accounting for 59 percent of U.S. AIDS cases in 2006. In some urban areas, the HIV infection rates rival those of Africa. Nowhere is this more shocking than in the nation's capital, where one in 20 Washingtonians have HIV and one in 50 has AIDS.
Through important public health programs, such as the Ryan White HIV/AIDS Program, the U.S. President's Emergency Plan for AIDS Relief, the Global Fund to Fight AIDS, Tuberculosis and Malaria, the Bill and Melinda Gates Foundation and the Clinton Foundation, we have made enormous strides in making life-saving treatments accessible to HIV-infected individuals throughout the world. Despite this heroic achievement, only a fraction of those individuals in developing countries who need antiretroviral therapy are receiving it. The stark reality is that for every person with HIV who is placed on therapy, about three more individuals become newly infected with the virus. The rate of new HIV infections far outpaces our ability to supply a lifetime regimen of HIV medication to everyone who needs it.
Further scale-up of lifesaving HIV treatment programs is critical. However, treatment alone will not end the AIDS pandemic. Developing HIV prevention strategies, including a vaccine, remains an extremely important goal. A number of proven strategies to prevent HIV transmission are already available, including education and behavior modification; condom usage; medically supervised adult male circumcision; harm-reduction approaches such as needle and syringe exchanges for injection drug users; and antiretroviral drug regimens for HIV-infected pregnant women to prevent mother-to-child HIV transmission of the virus. NIAID is testing other prevention strategies, such as microbicide gels or creams that can be applied prior to sexual intercourse and preventive regimens of antiretroviral drugs, that we hope will prove successful. Ideally, a vaccine that prevents HIV infection would be a core component of our prevention program.
Recently, NIAID convened a scientific summit to examine the state of HIV vaccine research and determine how best to move the field forward. Based on that discussion, it became clear that although it is important to maintain our approach to identifying promising HIV vaccine candidates and clinically testing those candidates when appropriate, it also is imperative that we place greater emphasis on the basic research necessary to address the many unanswered questions that remain about HIV. We must understand how to create a vaccine that induces a protective immune response in people that is more effective than the immune response that results when someone is naturally infected with HIV.
By striking a better balance between fundamental HIV research and vaccine development and by fostering research across scientific disciplines, we can expand the body of knowledge needed to better understand this complex virus and develop a safe and effective HIV vaccine.
On HIV Vaccine Awareness Day, we applaud the thousands of volunteers, scientists, community members and health professionals who have been involved in HIV vaccine research and who continue to support and participate in this extremely vital area of public health research. We encourage all interested parties to join with us in our rededicated battle to find an effective HIV vaccine to end the scourge of AIDS.
Dr. Fauci is director of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health in Bethesda, Maryland.
NIAID Director Fauci Cancels Planned HIV Vaccine Trial
July 18, 2008
Anthony Fauci, director of NIH's National Institute of Allergy and Infectious Diseases, on Thursday canceled a planned trial of NIH's Vaccine Research Center's HIV vaccine candidate, saying that additional research is needed before the candidate is tested in humans, the New York Times reports.
According to the Times, Fauci's decision to cancel the trial came after several meetings with scientists to discuss a failed Merck vaccine candidate (Altman, New York Times, 7/18). Merck in September 2007 announced it had halted a large-scale clinical trial of its experimental HIV vaccine after the drug failed to prevent HIV infection in participants or prove effective in delaying the progression of the virus to AIDS. The vaccine candidate also might have put some trial participants at an increased risk of HIV.
The VRC candidate, called PAVE-100, is similar to the Merck vaccine in that both stimulate CD4+ T cells against HIV and both contain the cold virus adenovirus-5 (Kaiser Daily HIV/AIDS Report, 3/25). The VRC candidate also contained pieces of HIV strains from around the world to spark immunity (Chase, Wall Street Journal, 7/18).
The PAVE trial aimed to determine whether the vaccine could decrease HIV viral loads in people who received the vaccine but later contracted HIV, according to Fauci. However, Fauci said a smaller trial is needed to determine the vaccine's effect on viral loads before a larger trial is conducted. Announcing the cancellation Thursday, Fauci said researchers have realized they do not know enough about how HIV vaccines and the human immune system interact. He added that smaller studies are needed until scientists understand which immune reactions are most likely to prevent HIV (New York Times, 7/18).
VRC initially planned to enroll 8,500 people in the U.S. and Africa in the trial. In March, the agency scaled back the trial to 2,000 volunteers after the failure of the Merck HIV vaccine candidate in 2007 (Kaiser Daily HIV/AIDS Report, 3/25). Fauci on Thursday called for a "leaner, meaner" study of the vaccine candidate that aims to lower viral loads (Wall Street Journal, 7/18). According to the San Francisco Chronicle, Fauci said he wants to conduct a study that would address "one fundamental question: whether the vaccine works." The study needs to determine as soon as possible whether people who are vaccinated and subsequently contract HIV can control their viral loads better than those who contract the virus but had been given a placebo. According to the Chronicle, Fauci's "scaled-down test proposal will still do that."
At least 30 trial participants over five years will need to contract HIV after receiving the vaccine for a scaled-down trial to be effective, according to James Kublin, director of the HIV Vaccine Trials Network, which would have run the trial. It is unclear how many trial participants will need to enroll for 30 participants to contract HIV, according to the Chronicle (Russell, San Francisco Chronicle, 7/18).
Comments, Reaction Despite the trial's cancelation, NIAID in a statement said it "believes the vaccine ... is scientifically intriguing and sufficiently different from previously tested HIV vaccines to consider testing it in a smaller, more focused clinical study." Seth Berkley, president of the International AIDS Vaccine Initiative, said researchers "can still learn something from testing the PAVE candidate in humans" but that it is "not necessary to do so in a trial involving thousands, as called for in the PAVE 100 design" (Fox, Reuters, 7/17).
Fauci emphasized that the agency is "not willing to entirely shelve the concept" of the vaccine but that a "less expensive trial, with less people, that's focused on the question of whether the vaccine can lower viral load" is necessary (Lauerman, Bloomberg/Philadelphia Inquirer, 7/18). "Show me that the vaccine works by lowering the amount of HIV in the blood. Then we will move to a larger trial that will document the link with a particular immune response," Fauci said, adding that until then, a "large trial is not justified" (New York Times, 7/18).
Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition, said that researchers "wanted to see the smallest, most-efficient trial to answer the question" of whether it can decrease viral loads and that "PAVE-100 wasn't seen as small or efficient enough" (Bloomberg/Philadelphia Inquirer, 7/18).
HIV Vaccine Development "Frustrating, Challenging," but Progress Being Made, NIAID's Fauci Writes in Opinion Piece
August 6, 2008
In a CNN opinion piece in advance of his talk at the XVII International AIDS Conference in Mexico City on Wednesday, Anthony Fauci, director of NIH's National Institute of Allergy and Infectious Diseases, examines the progress against HIV/AIDS, as well as the work that "remains to be done." He writes that with his talk he hopes to "leave the audience with at least a tentative answer to an important question ...: Will we ever have a cure or a vaccine for HIV?" Despite "considerable success" in managing HIV and improving the length and quality of life for people living with HIV/AIDS, there are "no well-documented cases of anyone truly being cured of HIV," he writes.
He adds, "HIV vaccine development has been frustrating and challenging for a number of reasons, including the fact that the virus mutates rapidly, hides from the immune system, and targets and destroys the immune system cells that are successful in fighting and clearing most other viruses from the body." He writes, "With HIV we will have to do better than nature if we are to develop a vaccine."
Although no "avenues of prevention" are "more essential than an HIV vaccine," the world's "best hope for eradicating HIV ... may be to diagnose and treat people aggressively very early in infection," he writes. Fauci adds, "Even if the virus is not completely eradicated ... early, intense treatment, perhaps with the help of immune-boosting drugs, might keep the reservoir small -- and the immune system strong -- thereby allowing a person to come off therapy. This would be a 'functional' cure. Other approaches are being pursued as well."
A "cure is critical to our attempts to ultimately contain the pandemic," Fauci writes. He adds, "As antiretroviral therapy is at present a lifelong commitment, it is extremely unlikely that we will have the logistical or financial capacity to reach and treat -- indefinitely -- everyone who requires antiretroviral therapy."
Fauci writes that he is "cautiously optimistic that we will be able to cure some patients under certain circumstances" and "develop a vaccine that will protect some people against HIV infection or slow the progression of disease in some patients who do get infected." Fauci invokes the conference theme, concluding, "we need 'Universal Action Now' to accelerate the exceptional momentum of the past few years ... in delivering proven tools of HIV prevention and therapy to communities around the globe" (Fauci, CNN, 8/5).
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