HIV: human vaccine still depends on wide studies

Publicação: 26 de August de 2014

Brazilian researcher is part of a study able to point solutions from the yellow fever vaccine vírus

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Research by Brazilian and American scientists points to a new paradigm to elaborate a vaccine against the virus. Results are promising and expected anxiously, especially by the poorest populations

For years scientists have studied ways to contain the advance of the HIV infections. Currently, 35.3 million people worldwide live with the virus, from which 69% are in sub-Saharan Africa. The problem that affects mainly the tropical countries still has no cure and, to have its dissemination controlled, more time is needed to present effective results for humans.

According to the head of the Flavivirus Molecular Biology Laboratory from the Oswaldo Cruz Institute (IOC/Fiocruz), Dr. Myrna Bonaldo , a great number of clinical tests have been conducted by the scientific community. Until now, the only one to show positive results in humans was the product RV133 in Thailand. The first analysis  pointed that about 32% of the participants vaccinated with the RV144 showed a lower risk of infection by the HIV than the placebo group.

The data, however, are analyzed carefully, especially because the indexes are still low. “Thailand’s case is still not enough to think in a more general approach. Once there is any kind of successful case, the application of clinical tests in distinct populations would be necessary to evaluate how extensive the vaccine would be. Any kind of successful experience will only be validated with wider studies”, says the scientist.

There are 35 clinical tests in course for a vaccine against HIV in the world, according to data from the International AIDS Vaccine Initiative’s (IAVI). However, the creation of an effective method to immunize humans is hampered due to the fast ability of the virus to mutate and multiply in the organism. Currently, the most effective control measure is the antiretroviral therapy, but the World Health Organization (WHO) estimates that the drugs are available to only 27.4% of the infected people.

Innovative research

Researcher Myrna Monaldo is one of those responsible for a study  developed by Brazilians and North-Americans, and published on Nature Magazine in 2012, that points to a new paradigm for the development of a vaccine against the virus. The focus is on the T CD8 cell, known for eliminating invading components from the human body. This organism, as the analysis showed, has the ability to kill HIV infected CD4 cells in some people. This is an innovation fighting the disease, once most of the researches aim to create a vaccine using antibodies.

The work is based on the patented method from 2005 from the Oswaldo Cruz Foundation and developed by the Brazilian scientist. The study consists on using the yellow fever vaccine as a platform in which genetic modifications capable of immunizing against other diseases are inserted. “What we are trying to see is if the modified yellow fever virus we have created has a good vaccine potential. Once we have any promising candidate, we could try the same approach for HIV”, explains.

The experiences involve Rhesus monkeys in the USA by the collaborating researcher David Watkins from Miami University. Out of the species used in the studies, some received the protecting T CD8 cell production inducer compounds and others not. Then, all the animals were inoculated with the SIV virus, that affects especially the monkeys and is similar to the HIV. Those which received the T CD8 production inducers presented a reduction in the virus replication up to 10 times, in the acute phase, in comparison to the group that did not receive the compound. The results are promising and expected anxiously.  Especially by the poorest populations.…