HIV vaccine
The HIV vaccine is an experimental preventive measure aimed at eliciting an immune response against the human immunodeficiency virus (HIV), which can lead to acquired immunodeficiency syndrome (AIDS). Unlike traditional vaccines that build immunity based on clear natural responses to infections, developing an effective HIV vaccine has proven challenging due to the virus's ability to evade immune detection and its rapid mutation rate. Researchers are exploring various vaccine strategies, including DNA vaccines, recombinant vector vaccines, and component (subunit) vaccines, each designed to stimulate the production of antibodies against HIV. The complexity of HIV infection, which can remain dormant without causing disease for years, adds another layer of difficulty in vaccine development.
Clinical trials, including those testing innovative approaches such as mRNA technology and preemptive vaccines, are ongoing in hopes of creating a safe and effective vaccine. With advancements in genetic engineering and modern medical techniques, there is renewed optimism in the scientific community for finding a viable HIV vaccine. This endeavor represents a crucial step toward preventing HIV transmission and reducing the burden of AIDS globally.
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Subject Terms
HIV vaccine
- ALSO KNOWN AS: Human immunodeficiency virus vaccine
Definition
A vaccine prevents disease by enabling the body’s immune response to an infectious agent. Vaccines contain elements of the infectious agent in preparations that are not meant to cause disease, but to stimulate the production of antibodies against the infectious agent. These antibodies prevent disease development. Although rare cases of persons with immunity to the human immunodeficiency virus (HIV) have been reported, mostly, natural immunity to HIV infection has not been effectively isolated or studied. Research on HIV vaccines was ongoing in the twenty-first century.
Development Challenges
Typical vaccine development procedures look at how the body naturally protects itself from reinfection with a disease-causing agent. If someone has mumps or measles as a child, that person will not suffer a second bout with the disease because their body has built up a natural immune antibody response to the viruses causing these diseases. Scientists look at antibodies produced by immune people and try to reproduce the same response with a vaccine. Researchers developing HIV vaccines are challenged because they lack this natural immune response model.
HIV infection is not a disease until the infection reduces a specific type of white blood cell (CD4+ T cells) to a very low level. Once this CD4 count lowers enough, the HIV-infected person will have acquired immunodeficiency syndrome (AIDS). Vaccines prevent disease, not infection. People can carry HIV infections for years without developing AIDS. HIV vaccine development aims to immunize against the infection, and not only against the disease. This is another significant challenge for HIV vaccine development. An additional challenge to the development of an HIV vaccine comes from the virus’s tendency to mutate rapidly. This makes it challenging to recognize mutations and target them effectively.
Impact
HIV vaccination provides hope for AIDS disease prevention and for protection against the transmission of HIV infection. Experiments with three main vaccine approaches involve deoxyribonucleic acid (DNA), recombinant vector, and component vaccines. All three approaches aim to produce antibodies against HIV.
DNA vaccines use parts of the HIV genetic code, a tiny ring of HIV DNA called a plasmid. Needle-free injection technology directly pushes DNA plasmids into the skin and immune cells. Electroporation devices increase skin cell plasmid uptake by using electrical pulses that open cell pores, admitting the plasmids. Once inside skin immune cells, the HIV genes produce HIV proteins (antigens). These antigens would provoke an immune antibody response protecting against HIV infection.
Recombinant vector vaccines use a carrier to bring HIV genes into the body. A part of the HIV genetic code is combined with the genetic code of another virus, a virus that typically does not cause human disease. This recombinant DNA, after introduction to the body, becomes a vector for the HIV genes. As with DNA vaccines, the newly introduced HIV genes would produce HIV antigens, resulting in host antibody production and HIV immunity.
Both of the preceding techniques involve modern genetic manipulations. Component or protein vaccines, also known as subunit vaccines, use portions of HIV to stimulate an immune response. This is the classic type of vaccine, but even this classic approach now uses modern gene technology. Genetic engineering is used to produce HIV portions used in these component vaccines.
Researchers have also explored combining these vaccine approaches to overcome the challenges of formulating an HIV vaccine. HIV vaccine development must overcome intricate challenges. Studies have also been focused on boosting cellular immunity and developing therapeutic vaccines. Clinical trials were underway in the twenty-first century to create an approved, effective, and safe HIV vaccine. Examples of these trials include the 2023 trial of a preemptive HIV vaccine, VIR-1388, designed to induce an immune-specific HIV response and multiple human trials of mRNA-based vaccines begun in 2022. Modern technologies provide hope and promise with this important disease prevention endeavor.
Bibliography
"Clinical Trial of HIV Vaccine Begins in United States and South Africa." National Institutes of Health (NIH), 20 Sept. 2023, www.nih.gov/news-events/news-releases/clinical-trial-hiv-vaccine-begins-united-states-south-africa. Accessed 6 Oct. 2024.
"The Development of HIV Vaccines." History of Vaccines, historyofvaccines.org/vaccines-101/future-immunization/development-hiv-vaccines. Accessed 6 Oct. 2024.
Grandi, Guido, editor. Genomics, Proteomics, and Vaccines. Hoboken, N.J.: John Wiley & Sons, 2004.
"Innovative HIV Vaccine Approaches Yield Potential for Broad Protection Against Viral Strains." News-Medical, 2 July 2024, www.news-medical.net/news/20240702/Innovative-HIV-vaccine-approaches-yield-potential-for-broad-protection-against-viral-strains.aspx. Accessed 6 Oct. 2024.
Morrow, Matthew P., and David B. Weiner. "DNA Drugs Come of Age." Scientific American, vol. 303, no. 1, July 2010, pp. 48-53.
Plotkin, Stanley A., Walter A. Orenstein, and Paul A. Offit. Vaccines. 5th ed., Philadelphia: Saunders/Elsevier, 2008.