HIV vaccine trial yields positive results

Research released on this World AIDS Day (1st) noted that a vaccine model caused an immune response in study participants. The conclusion of the study, which was signed mainly by Americans, collaborates to understand how to induce antibodies that are effective in combating HIV.

A major dilemma in making an effective HIV vaccine is that the virus is constantly changing. One way around the dilemma is to induce an immune response based on highly neutralizing antibodies (bnAbs). Studies have already shown that they are able to protect against infection by the pathogen that causes AIDS.

“These antibodies [altamente neutralizantes] bind to the virus and prevent it from entering the cell – we say that the virus has been neutralized. This is essential to contain a viral infection”, says Aguinaldo Roberto Pinto, who does not author the article and is a professor at the department of microbiology, immunology and parasitology at UFSC (Federal University of Santa Catarina).

Antibody production is associated with cells called B lymphocytes. However, for highly neutralizing antibodies, these lymphocytes are rare and therefore production is insufficient even in people living with HIV.

“If you take a person who has HIV, they have a lot of B lymphocytes that are making antibodies against the virus, but they are rarely making [aqueles que são] neutralizing agents”, says Pinto.

Formed by 120 copies of the outermost HIV protein, called GP120, the new vaccine stimulated the B lymphocyte precursor cells. may be helpful in disease prevention

In total, the study had 36 participants. Of those, 35 showed responses in B lymphocyte precursor cells associated with the antibody that is effective against HIV. In addition, the immunizer’s safety standard was measured – an important objective for studies like this one, which is phase one.

new phases

For Pinto, the findings of the study are significant that the vaccine can work, but there is a lack of larger and longer studies to measure whether the generation of antibodies induced by the vaccine will really cause protection against HIV.

This is a dilemma that every virus vaccine study faces. A phase three study requires a large sample and follow-up over a period of time to compare the infection rate of the placebo group with that which received the vaccine.

But that can take years in an AIDS vaccine trial because participants need to be so well informed about preventing the virus. In addition, the virus is transmitted through sexual intercourse or sharing objects. In this way, transmission can be considered more difficult compared to other pathogens, such as Sars-CoV-2, whose transmission is mainly through the air.

Therefore, Pinto says he believes that, even with the promising results, the new vaccine may take a long time to have new data on its effectiveness. “When it gets to a phase three, it will be a problem that always appears in vaccines against HIV, which is to know if people are going to infect or not in the real world”, he concludes.