Sunday, July 5, 2015

Human trials of HIV vaccine begin after partial success in monkeys

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% efficacy
The two-step vaccine not only protected half the monkeys, but their bodies produced antibodies that can be measured to show how well-protected the monkeys are.

In step 1, the test subject is given a shot of a weakened cold virus. This allows the genes of HIV to enter the body. In step 2, the test subjects received a very pure form of an HIV surface protein. This causes the body’s immune system to strongly react to the invader.

Scientists are hopeful that the experimental vaccine is effective due to the combination of high exposure rate and the number of test subjects that did not get infected during the trial.

One of the doctors involved in the study said that they are not certain the vaccine that is protecting the monkeys will protect humans.

Vaccine holds promise

But in a statement, Dr. Mary Marovich, who is Director of Vaccine Research at the National Institute for Allergy and Infectious Diseases, NIAID, described the new AIDS vaccine as promising.

“I do think that their results are impressive. Even protecting half of the people who are exposed to the virus would be a major accomplishment. It could ultimately end the epidemic when you use it in combination with other measures.”

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