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Potential HIV Vaccine Moves Into Next Testing Phase

author

Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockJan 1 2011, 00:00 UTC

Artist's impression of the Human Immunodeficiency Virus (HIV). Liya Graphics/Shutterstock

The results for the first phase of the HIV vaccine, SAV001, are in and they are promising enough that the vaccine has been approved to move on  to Phase II of testing.

The results are published in the journal Retrovirology and show that the vaccine is safe to be administered to humans without serious side effects. SAV001, which was developed at Western University in Canada, was tested on 33 HIV-positive volunteers and it showed to be effective in triggering an anti-HIV immune response in the patients.

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"We were very excited with the Phase I results," team leader Chil-Yong Kang said in a statement. "The trial demonstrated that our vaccine stimulates broadly neutralising antibodies that will neutralise not only single sub-types of HIV, but other sub-types, which means that you can have the vaccine cover many different strains of the virus."

While the result is encouraging, the vaccine has not been shown to actually prevent the viral infection in humans. That will be tested in Phase II, which is now awaiting the approval of government regulatory agencies and might begin in late 2017.

Phase II will involve 600 HIV-negative volunteers, 300 from the general population and 300 from high-risk categories like sex workers, men who have sex with men, and people living with an HIV-positive partner.

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“It remains to be determined whether this immune response triggered by the vaccine will prevent HIV infection in humans, but we are hopeful,” added Kang.

Vaccines usually use dead ("killed") or weakened viruses to “train” the human’s immune system. This approach was believed to be too dangerous using HIV as scientists weren’t sure it could be made harmless.

The Western University researchers genetically modified the HIV virus using genetic material from honeybees (specifically the melittin signal peptide). The altered HIV virus is less virulent, can be replicated more easily and it can be safely inactivated.  

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This breakthrough allowed the team to produce the first preventative HIV vaccine using genetically modified killed whole-virus, a strategy which has been successful in common vaccines like flu and polio.

“If we can show that this vaccine is effective in preventing people from contracting HIV, we can stop the AIDS epidemic and that would be tremendous,” said Kang. “It would be a tremendous contribution to humankind, and it would make all of our efforts worthwhile.”

If Phase II is successful, the next phase will be conducted worldwide with 6,000 volunteers and it would show the effectiveness of the vaccine in the larger population.

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Currently, people can protect against infection  by educating themselves about HIV and how it is transmitted, using condoms and Pre-exposure prophylaxis (PrEP), a daily pill with virtually 100 percent efficiency in stopping the virus.

While news of a vaccine is promising, ignorance and stigma still dramatically affects the 35 million HIV-positive people worldwide.


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