Published: 09:45 GMT, 3 July 2015 | Updated: 14:09 GMT, 3 July 2015
An experimental vaccine completely prevented HIV infection in half of monkeys given the jab, a new study found. The monkeys were given the vaccine and then exposed to high doses of an aggressive virus that is the equivalent of HIV in humans. The results were so positive they spurred Johnson & Johnson to test the vaccine in people. The international trial is underway in 400 healthy volunteers in the United States, East Africa, South Africa and Thailand.
An experimental vaccine completely prevented HIV infection in half of monkeys given the shot, a study found
It is the first time since Merck's failed 2007 trial that a major pharmaceutical company has sponsored clinical development of an HIV vaccine, said Dr Dan Barouch, a vaccine researcher at Beth Israel Deaconess Medical Center and the Ragon Institute of Massachusetts General Hospital, MIT and Harvard. Some 35 million people are infected with HIV, the virus that causes AIDS. Since it began spreading 30 years ago, AIDS has killed 40 million people worldwide. Despite progress in treatments, experts believe a vaccine is the best hope for eradicating the disease. In a pair of studies Dr Barouch and colleagues at Johnson and Johnson and elsewhere tested a two-step vaccine, which involves priming the immune system using a weakened version of the cold virus to sneak HIV genes into the body. The second phase involves injecting individuals with a purified HIV surface protein designed to provoke a strong immune response. The company is using the same prime-boost strategy in its Ebola vaccine, now in early-stage human trials, Dr Paul Stoffels, Johnson & Johnsons's chief scientific officer and worldwide chairman, pharmaceuticals, told Reuters. Dr Stoffels said the HIV vaccine trial in monkeys was designed to test the limits of the vaccine, exposing the animals to high levels of an aggressive virus that attacks non-human primates known as simian immunodeficiency virus, a close cousin to HIV.
Some 35 million people are infected with HIV, the virus that causes AIDS. Since it began spreading 30 years ago, AIDS has killed 40 million people worldwide.
Pictured is the virus in human lymphatic tissue
HIV: the facts explained by a medical expert
The virus was potent enough to infect 100 per cent of unvaccinated animals after six exposures. Even so, half of the animals who got the vaccine were completely protected.
Dr Stoffels said the infection rate per exposure in the trial is about 100 times greater than what is typically seen in humans. Johnson & Johnson expects the vaccine to prove even more effective in people, but even if the vaccine only protects half of those people who get it, 'it will still have an enormous public health impact,' Dr Stoffels said. If all goes well with the early-stage trial, he expects a larger, phase 2b study to start in the next 18 to 24 months. Phase 2b studies test how well drugs works at the prescribed dose. The research was published online in the journal Science.
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