Promising response to �Thai� HIV vaccine

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Background

Thursday 24 September 2009

Researchers in Thailand backed by US army make breakthrough in search for preventive innoculation against Aids

An experimental vaccine has become the first of its kind to significantly prevent infection with HIV, scientists said this morning, raising hopes of a major breakthrough in the fight against Aids.

The world's largest Aids vaccine trial of more than 16,000 volunteers in Thailand found the risk of becoming infected with HIV was cut by almost a third.

The US army sponsored the trial with the National Institute of Allergy and Infectious Diseases. Colonel Jerome Kim, who helped to lead the study for the US army, said it was "the first evidence that we could have a safe and effective preventive vaccine".

Recent failures had led many scientists to believe that such a vaccine might not be achievable.

The National Institute's director, Dr Anthony Fauci, warned it was "not the end of the road," but said he was surprised and very pleased by the outcome.

"It gives me cautious optimism about the possibility of improving this result" he said. "This is something that we can do."

Every day, 7,000 people worldwide are newly infected with HIV; 2 million died of Aids in 2007, the UN agency Unaids estimates.

The Aids Vaccine Advocacy Coalition, an international group that has worked toward developing a vaccine, welcomed the results of the trial as "an historic milestone".

The executive director, Mitchell Warren, said: "There is little doubt that this finding will energise and redirect the Aids vaccine field."

Thailand's ministry of public health conducted the study, which used strains of HIV common in Thailand.

Scientists stressed it was not known whether such a vaccine would work against other strains elsewhere in the world. The study was done in Thailand because US army scientists did pivotal research in that country when the Aids epidemic emerged there, isolating virus strains and providing genetic information on them to vaccine makers.

The study tested a two-vaccine combo in a "prime-boost" approach, where the first one primes the immune system to attack HIV virus, and the second one strengthens the response.

New infections occurred in 51 of the 8,197 people given vaccine and in 74 of the 8,198 who received dummy shots. That worked out to a 31% lower risk of infection for the vaccine group.

Scientists discover new vaccine that prevents HIV infection | World news | guardian.co.uk

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Human trials of HIV vaccine begin after partial success in monkeys
Sola Ogundipe
July 05, 2015

The success of an experimental vaccine trial with rhesus monkeys is motivating a pharmaceutical company to undertake experimental HIV vaccine tests in Thailand, East and South Africa, and the United States of America US, with 400 healthy participants taking part in the first phase of the trials.

Scientists say the vaccine protected half of a batch of monkeys against the Simian Immunodeficiency Virus, SIV, which is very similar to HIV, the virus that causes AIDS.

This development came to light just as a former researcher at Iowa State University, was jailed for fraudulently securing millions in funds for further research on a potential vaccine for HIV that turned out to be fake.

Janssen, the pharmaceutical arm of Johnson & Johnson, is testing the vaccine on humans, for the first time in eight years since a pharmaceutical company last attempted an experimental HIV vaccine trial on humans.

Researchers are optimistic that if results of the current human study are as good as the result in the non-human primate test subjects, then a larger scale clinical trial could begin within the next two years.

A study published in the journal Science, revealed that monkeys used for the new study received shots of the experimental vaccine and were then injected with SIV, which is very similar to HIV. A total of six injections of SIV were given to the monkeys to find the point where the vaccine would fail.

50% efficacyScientist jailed for fake claim

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HIV vaccine research requires unprecedented path, expert suggests
National Institute of Allergy and Infectious Diseases
July 12, 2016

Virus poses unique challenges, demands innovative strategies

Summary:Because the body does not readily make an adequate immune response to HIV infection, creating a preventive HIV vaccine remains a formidable challenge for researchers. To succeed in this endeavor, scientists have responded with complex, creative and elegant approaches unparalleled in other vaccine research pursuits, according to a new article. Share:

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The development of an effective vaccine to prevent HIV infections would represent a critical step toward ending the HIV/AIDS pandemic. Thus far, the only large clinical trial for an HIV vaccine to show promise was the RV144 study conducted in Thailand in 2009, which resulted in a modest 31 percent reduction in infection. Researchers are working to improve on the results of RV144 and also have launched efforts to create vaccines that induce broadly neutralizing antibodies that can block a wide range of HIV variants. However, because the body does not readily make an adequate immune response to HIV infection, creating a preventive HIV vaccine remains a formidable challenge for researchers. To succeed in this endeavor, scientists have responded with complex, creative and elegant approaches unparalleled in other vaccine research pursuits, according to a new commentary from Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

Dr. Fauci explains that certain immune cells (B cells) typically produce neutralizing antibodies (NAbs) to most viruses within days or weeks of infection. These NAbs allow the infected person to clear that viral strain and enjoy lifelong immunity. This principle is used to create most viral vaccines, in which the killed or weakened virus itself or selected immunogens--benign components of virus -- are used to induce the production of NAbs without establishing an infection. People infected with HIV, however, do not readily produce Nabs and when they do, they are not produced in sufficient time to clear or even control the infection. Because of this, efforts to vaccinate individuals with HIV immunogens and coax their immune systems to establish protective NAbs have not yet been successful.

To overcome these difficulties, HIV vaccine researchers employ methods and technologies rarely seen in other branches of vaccine research, such as rigorous analyses of the B cell repertoire and its evolution and sophisticated structural biological techniques that determine precise molecular conformation of viral components and their interaction with NAbs. Dr. Fauci writes that the breadth and diversity of efforts to establish broadly neutralizing HIV antibodies in the absence of infection will be remembered, if successful, as the most elegant and complex approach toward the development of a vaccine in history. If unsuccessful, these efforts will offer comprehensive evidence that it will be unlikely that a vaccine will be able to induce broadly neutralizing antibodies. Hopefully, the former and not the latter will be the case.

sciencedaily.com

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Major HIV vaccine trial in South Africa stokes hope
Ryan Lenora Brown and Leonard Bernstein
Brown reported from South Africa, and Bernstein reported from Washington.
November 25


In South Africa, Thembi Dlamini, 29, is screened at a clinical research site to participate in the trial.
(Ryan Lenora Brown/For The Washington Post)

VERULAM,
Aruna Bhoola, a pharmacist at the Medical Research Council in Verulam, South Africa, checks samples of the HIV vaccine.
(Ryan Lenora Brown/For The Washington Post)
At the Medical Research Council in Verulam, South Africa, a poster describes the way HIV drugs work.
(Ryan Lenora Brown/For The Washington Post)