Brazil begins testing HIV vaccine on monkeys

São Paulo – The vaccine against HIV started its testing phase this week on monkeys. The vaccine was developed by the Medical School of the University of São Paulo in a partnership with the Butantan Institute. Four monkeys started being immunized with the vaccine, which contains parts of the virus.

According to Edecio Cunha Neto, one of the scientists responsible for carrying out the project, what is special about this vaccine is that it uses parts of the virus that do not change. “One of the biggest problems in producing an HIV vaccine is that it’s hypervariable,” he points out. He explained that the genome of the virus in two different people may vary up to 20%. “Among the components we’ve chosen to include in the vaccine are only the most well-preserved regions of the virus, i.e., those that don’t change from one HIV virus to the other,” he said.

Cunha Neto further explained that they did what is termed “rational design”, in order to make the vaccine effective against as many specimens of the virus as possible, in a large number of individuals.

After trials are conducted with four animals, new experiments will be performed with a group of 28 monkeys and three different virus types, all of which altered with parts of the HIV virus. “The combinations of these three viruses are, up to the moment, the best combinations to induce potent immunological responses in primates. So we’ll select, from the four combinations, the one that produces the strongest response, and we’ll use this combination for human testing,” he clarified.

If successful, the vaccine is expected to induce a stronger response in those immunized against the virus, preventing its transmission and improving patients’ quality of life. “The vaccine will reduce the virus load considerably and kill infected cells, but the infection can hardly be eradicated. Transmission to another person will be blocked, because the viral load will be too low.”

Bearing in mind the recent protests against animal testing, which has led an institute in São Paulo to shut down, Cunha took the opportunity to say that the animals are well-treated. “The animals in this study don’t suffer in any way. Even when their blood is collected or they’re being vaccinated, they’re anesthetized,” he emphasized.

The scientist also advocated the use of animals in tests. “It’s not possible to replace animal testing with a simpler culture test or a laboratory test. Animal testing will allow us to evaluate the performance of a new vaccine, a new drug, in the entire organism,” he argued