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The vaccine against the HIV virus is being studied, 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, the vast majority failed to get past the second phase of testing the vaccine and have not been made available to the population.
HIV is a complex virus that acts directly on the main cell of the immune system, causing changes in the immune response and making it more difficult to fight. Learn more about HIV.
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 flu 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 a part of the live or dead virus, 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, however these antibodies 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 HIV vaccine is the fact that the virus attacks the cell responsible for regulating the immune system, the CD4 T lymphocyte, which causes uncontrolled antibody production. In addition, the HIV virus can undergo several changes, and may have different characteristics between people. Thus, even if the vaccine for the HIV virus is discovered, another person may carry the modified virus, for example, and thus the vaccine will have no effect.
Another factor that makes studies difficult is that the HIV virus is not aggressive in animals, and therefore, 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 study phase, which corresponds to the phase in which vaccine is administered to a larger number of people.
Learn more about the vaccine testing phases.
In addition, several types of HIV with different characteristics have been identified, mainly related to the proteins that constitute it. Thus, due to diversity, making a universal vaccine is difficult, as the vaccine that may work for one type of HIV may not be as effective for another.