Childhood vaccination can prevent approximately 4 million deaths yearly, and, as estimated by the Centers for Disease Control and Prevention – CDC (2023), immunization can contain over 50 million deaths between 2021 and 2030. These statistics expose the importance of vaccination for the longevity of human life and how vital these active immunizations are. What is the difference between live attenuated, inactivated, and DNA vaccines? As time has passed, the production of vaccines has undergone significant improvements. The methods and technologies utilized in the production process have evolved, developing various immunization production techniques. This essay compares and contrasts three approaches to making vaccines: live attenuated, inactivated, and DNA vaccines from the perspective of the production method, efficacy, advantages, and drawbacks.
The main distinction between the three vaccine types is how they are produced and act in our bodies. There are significant variations among inactivated, live-attenuated, and DNA vaccines. These differences relate to the materials introduced into the body and the antibodies’ ability to recognize, combat, and remember them for future infections. Inactivated pathogen vaccines are made by deactivating the pathogen through heat, radiation, or chemicals. The pathogen loses its ability to cause illness but keeps its immunogenicity so the immune system can still recognize it.(Wodi & Morelli, n.d.; Vetter et al., 2017). Instead, live-attenuated vaccines are made using RNAi and reverse genetics, where current virus genes are combined with altered viruses from the same strain to create the vaccine; the live viruses in the vaccine are weakened but can still cause infection to some extent, leading to solid immunity development in the host (Shabir, 2021; Wodi & Morelli, n.d.; Vetter et al., 2017). In contrast, DNA vaccines contain a plasmid with a viral promoter, desired gene, and transcriptional sequence; administered via injection, host cells take up the plasmid, which synthesizes the protein, but they do not replicate or integrate into the host’s DNA when antigens are presented to the immune system, they trigger an immune response. (Donnelly et al., 1996; Saade & Petrovsky, 2012; Vetter et al., 2017 ). All these three types of vaccines introduce some material into the body to start an immune response and produce memory cells that begin to replicate and produce antibodies rapidly to combat future similar infections, with the difference being that live attenuated is produced with weakened viruses or bacteria, inactivated is made with no live material. DNA uses part of the virus’ genes to stimulate an immune response and deliver cell memory for future infections.
Certain vaccines may require more than one dose, mainly inactivated vaccines. Typically, the initial injection does not provide complete protection against the disease. Protective immunity usually develops after the second or third dose. Instead, live vaccines elicit an immune response more like a natural infection than inactivated vaccines. Still, that does not mean that live attenuation never requires extra amounts; sometimes, a second dose is needed to produce an extremely high level of immunity in the population. (Wodi & Morelli, n.d.). However, inactivated vaccines generate mainly antibodies and comparatively little cellular immunity, which may require additional doses to increase their effectiveness over time. Like inactivated vaccines, DNA vaccines have lower immunogenicity than protein-based vaccines (Saade & Petrovsky, 2012). This may require additional doses to ensure complete immunization. However, other factors can affect whether more injections are needed, such as how these doses are given and mutations; as the injection is administered orally usually requires more than one dose, it is because, in this way, the delivery can be less efficient than the injected one due to the acids contained in our gastric system (Vela Ramirez et al., 2017). Regarding mutations, independent of the method or technology used in the vaccine production, once the pathogen changes, it is necessary to update the vaccine and new doses taken to combat the new strain.
In general, the techniques presented in this article have their advantages and disadvantages. Developed in the 18th century (Plotkin, 2014), live attenuated vaccines immediately generate a robust immune response because they maintain the original antigens and imitate a natural infection. Despite being weakened, they can cause harm to the host, particularly for individuals with weakened immune systems (Giese, 1998; Inactivated, n.d.; Immunisation, n.d.; Li et al., 2020). Vaccines like Bacillus Calmette Guérin (BCG), Measles, Mumps, Polio Sabin, Rotavirus, Rubella, Varicella, and Yellow Fever(Office of Infectious Disease and HIV/AIDS Policy (OIDP), 2022) use this method. One century later, the inactivated vaccine was developed (Plotkin, 2014) and is considered safer than the live attenuated vaccine as it can produce a robust immune response. On the other hand, one of its drawbacks is that the inactivation process may alter the epithet, requiring more than one dose to provide complete immunization (Giese, 1998; Immunisation, n.d.; Li et al., 2020; Live, n.d.). This method is used in many vaccines such as Cholera, Hepatitis A virus, Influenza, Plague, Polio Salk, Rabies, and Typhoid (OIDP, 2022). In contrast, DNA vaccines were developed recently, dated in the 90s (Plotkin, 2014) and are deemed safe and easily tolerated. They are also highly versatile in adapting to new pathogens and native antigen expression(Li et al., 2020). However, they have lower immunogenicity, require low-temperature storage and transportation, and there is a risk of RNA-induced interferon response. This method is recent, and its usage in humans is new and restricted; during the pandemic, some countries approved the use in humans(Blakney & Bekker, 2022, para. 2), but there are many studies in curse for illnesses like cancer(Lopes et al., 2019), Dengue and Zika (Mourosi et al., 2022), what makes this method very promising. Despite the differences, all these types have the same objective: to make our bodies act against invaders and strengthen our defence system.
Vaccines save millions of lives every year, avoid pandemics, and have a crucial role in the combat of several illnesses around the world. Vaccines come in different types, such as inactivated, live attenuated, and DNA. However, these types have the same operation principle; they introduce materials into our bodies that start an immune response and, in consequence, produce antibodies and memory cells, which help protect us against specific pathogens. These vaccines have advantages and disadvantages and can be applied in particular usages; live vaccines are very efficient but risky for weak immune systems. Inactivated vaccines are safer but may need more doses. DNA vaccines are safe yet less effective, require special storage, and are new for humans. Vaccination has been used for over three centuries to fight and prevent diseases and pandemics. The success of this technology and the constant improvements permit humanity to live longer and better. Moreover, traditional vaccines are making way for new research on DNA vaccines that show promise in hastening the prevention and treatment of old and more unused illnesses.
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