U of M researcher using the chickenpox virus to develop HIV vaccine

A University of Manitoba researcher has gotten one step closer to using the chickenpox virus to develop a vaccine against HIV.

The study, led by Dr. Kelly MacDonald, shows the chickenpox virus may hold the key to inducing the human body to produce a safe, long-lasting, protective immune response to HIV.

MacDonald is a professor of internal medicine, immunology and medical microbiology at the U of M and professor of immunology at the University of Toronto.

“Our study investigated an important safety concern that posed a barrier to this vaccine strategy. Now, with our findings, the stage is set to move forward with testing a chickenpox-based HIV vaccine,” said MacDonald in a news release.

According to the U of M, the study is the first in the world to demonstrate that the chickenpox vaccine, when given to people who are already immune to it, does not trigger an unwanted “HIV-welcoming” immune state in the bloodstream.

The project used researchers from the University of Toronto and the Kenyan AIDS Vaccine Initiative – Institute of Clinical Research at the University of Nairobi, and was supported by the Canadian Institutes of Health Research.

“A blended chickenpox/HIV vaccine would take advantage of the fact that chickenpox virus undergoes silent cycles of reactivation in the body. Each time it ‘wakes up’ from its dormant state, the body’s immunity quickly controls it, and the immunity is boosted,” MacDonald said. 

“The idea is to combine what we call ‘HIV inserts’ with the chickenpox virus. We expect that each time the chickenpox virus is reactivated, it will also refresh immunity to HIV.”

MacDonald said an international human clinical trial that used a different virus was unsuccessful and was stopped in 2007.

MacDonald’s study was conducted in Kenya using 44 healthy, HIV-negative women who were at low risk for HIV exposure and tested positive for immunity to chickenpox. The women were injected with a high-dose vaccine against only chickenpox, according to the university.

The study showed that 12 weeks post-vaccination, there was no significant difference in the frequency of activated HIV target cells, compared to pre-vaccination.

“This chickenpox vaccine passed this comprehensive safety examination,” MacDonald said. “Our results pave the way for the use of chickenpox virus as a vector for HIV vaccine development.”

MacDonald said the next steps are to continue testing the vaccine strategy using non-human primates and to develop a vaccine for a clinical trial in humans.