Our bodies have several ways to defend themselves against pathogens, which are organisms that cause disease. When the body detects a pathogen, it activates the immune system, a complex defence network designed to identify, attack, and destroy harmful invaders. A key part of the immune system is the antibody. Antibodies are specialized proteins designed to target a specific part of a pathogen, known as an antigen. Each antibody is shaped in a way that allows it to recognize and bind to a specific antigen. You can think of antibodies as the body’s police officers. Each officer is trained to identify a particular “criminal”, the antigen, and respond appropriately to stop it. However, just like training a police officer takes time, your body needs time to learn how to make the right antibodies. During this period, you are more vulnerable to getting sick. When your body is exposed to a pathogen for the first time, it begins to produce new antibodies that match that pathogen’s antigens. After the infection is cleared, your immune system stores the memory of those antigens. This allows your body to respond much faster if the same pathogens appear again. The challenge arises when your body encounters a new pathogen. Because it has never seen this antigen before, it does not yet have the antibodies needed to fight it effectively. This is where vaccines become important.
Vaccines work by introducing a weakened, inactive, or specific part of a pathogen, often the antigen, into the body. This does not cause disease, but rather activates the immune system. Your body responds by creating the antibodies needed to fight that antigen. Once these antibodies are made, your immune system stores the information, just as it would after a real infection. This means that if you encounter the actual pathogen in the future, your body already knows how to destroy it quickly and effectively. You can think of a vaccine as a practice drill for your immune system—a safe, controlled way to train your body to defend itself before the real threat appears. While conventional vaccines rely on weakened or inactive pathogens, modern vaccine technology can teach the immune system using only the genetic instructions for a single viral protein. This approach is based on mRNA.
RNA is a nucleic acid found in the body that closely resembles DNA. Like DNA, it carries genetic information, but there are key differences between the two. DNA is double-stranded and serves as a long-term storage system for genetic instructions, while RNA is typically single-stranded and temporary. RNA often functions as a messenger or as a molecule involved in various cellular processes. The three main types of RNA are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). In this paper, we will focus on mRNA and its role in vaccine technology. Messenger RNA (mRNA) is named for its role in carrying genetic instructions from DNA in the nucleus to the cytoplasm, where proteins are synthesized. Traditional vaccines usually work by introducing a weakened, inactivated virus or bacterium into the body. This exposure activates the immune system, allowing it to recognize and destroy the pathogens. mRNA vaccines, however, use a different strategy. Scientists identify the mRNA sequence that corresponds to a specific viral protein, typically a protein found in the virus’s outer surface. This synthetic mRNA is then delivered into the body’s cells, which temporarily use the instructions to produce the viral protein. Because this protein is foreign, the immune system recognizes it as a threat and begins producing antibodies against it. After the protein is made, the mRNA is naturally broken down by the body. What remains is an immune system that has learned to recognize the viral protein and can respond more quickly and effectively if the actual virus enters the body in the future. A helpful way to visualize this process is to imagine the immune system as a collector. Each time it encounters and defeats a new “opponent,” it keeps a memory of that opponent (in this case, the antibodies) so that it can respond faster the next time. mRNA vaccines essentially give the immune system a safe preview of the virus, allowing it to prepare without ever being exposed to the real pathogen.
Works Cited
“How do vaccines work?” World Health Organization (WHO), 25 February 2025, https://www.who.int/news-room/feature-stories/detail/how-do-vaccines-work. Accessed 24 December 2025.
“Messenger RNA (mRNA).” National Human Genome Research Institute, https://www.genome.gov/genetics-glossary/Messenger-RNA-mRNA. Accessed 24 December 2025.
“Ribonucleic Acid (RNA) Fact Sheet.” National Human Genome Research Institute, 24 May 2024, https://www.genome.gov/about-genomics/educational-resources/fact-sheets/ribonucleic-acid-fact-sheet. Accessed 24 December 2025.“What are mRNA vaccines and how do they work?” MedlinePlus, 21 November 2022, https://medlineplus.gov/genetics/understanding/therapy/mrnavaccines/. Accessed 24 December 2025.