HIV vaccine

The vaccine against the HIV virus is in the study phase, being researched by scientists worldwide, but there is still no vaccine that is really effective. Over the years there have been many hypotheses that the ideal vaccine would have been found, however, all of them have lost their effect.

Understand why HIV does not yet have an effective vaccine and the barriers encountered so far.

Because HIV doesn't have a vaccine yet

Currently, there is no effective vaccine against the HIV virus, because it behaves differently from other viruses, such as influenza or chicken pox, for example. In the case of HIV, the virus affects one of the most important defense cells in the body, the CD4 T lymphocyte, which controls the immune response of the entire body. The 'normal' vaccines offer part of the virus alive or dead, which is enough to make the body recognize the offending agent and stimulate the production of antibodies against that virus.

However, in the case of HIV, it is not enough to just stimulate the production of antibodies, because that is not enough for the body to fight the disease. HIV-positive people have many antibodies circulating in their bodies, but that is not enough, because they are not able to eliminate the HIV virus. Thus, the HIV vaccine should work differently from the other types of vaccines available against the most common viruses.

What makes it difficult to create the HIV vaccine

One of the factors that hinder the creation of the vaccine against HIV is the fact that the virus attacks the cell responsible for the regulation of the immune system, the CD4 T lymphocyte, which causes uncontrolled antibody production. In addition, the HIV virus can undergo several modifications, and may have different characteristics among people. Thus, even if the vaccine for the HIV virus is discovered, another person can carry the modified virus, for example, and thus the vaccine becomes have no effect.

Another factor that makes studies difficult is that the HIV virus is not aggressive in animals, and therefore, the tests can only be carried out with monkeys (because it has a DNA very similar to humans) or in humans themselves. Research on monkeys is very expensive and has very strict rules for the protection of animals, which make such research not always feasible, and in humans there are not many researches that have passed the 2nd phase of studies, which we explain below.

How vaccines are created

The vaccine creation process goes through 3 different phases:

Phase 1:

An experimental vaccine is tested with fragments of the virus on a small number of people, for example 100, and it is observed how your body reacts after the vaccine and what side effects arise. This phase lasts an average of 2 years, and if there are satisfactory results, the vaccine moves on to the 2nd phase. Many HIV vaccines have gone through this moment of hope.

Level 2:

The same vaccine will be tested on a larger number of people, for example 1000 people, and in addition to observing how your body reacts and the side effects, we try to find out if different doses are effective in order to find the appropriate dose, that has less harmful effects, but that is able to protect everyone, everyone.

Since the HIV virus has many subtypes around the world, research is often more difficult at this point, as the vaccine may be effective for a type of virus common in Africa, but it is not effective for the virus found in other countries, this vaccine is not considered effective.

Various researches around the world are in the second phase of testing, requiring cooperation at world level.

Phase 3:

Assuming that the same vaccine was successful until phase 2, it moves to the third phase, which consists of applying this vaccine to a greater number of people, for example 5, 000, and observing whether they are really protected or not.

However, even with the vaccine in the last phase of testing, it is important that the person starts to take the same precautions related to protection against contamination, that is, using condoms and not sharing syringes, for example. In addition, the absence of risky behavior is important to assess the efficacy and safety of the vaccine under study.

Types of HIV vaccine

There are 2 different types of vaccine, the HIV prevention vaccine, where most of the studies are focused, and also the therapeutic vaccine, which helps in the treatment against HIV, this one already exists and has been used in combination with antiretrovirals, with success in many countries. Learn more about advances in curing HIV, and how the therapeutic vaccine has been used in HIV-positive patients.