Vaccines are used to illicit an immune response in the body by imitating an infection from a disease. The immune system is trained to fight off the actual infection once your body has encountered it. Most vaccines work through two mechanisms, the antigen is used to specify the immune system’s adaptability to the pathogen itself and adjuvants which are used to stimulate the innate immune response through the stimulation Pathogen Recognition receptors (PRRs). The stimulation of PRRs is a necessary step in activating an adaptive immunity response.
Your immune system will take a few days to produce the antibodies necessary to fight off the infection, but after it has been to exposed an invading antigen, it defends your body much more readily. T-Lymphocytes are what’s kept around for the immune system’s “memory”, they recognize previous invaders and enable a swift immune response.
What are the types of vaccines?
Live Attenuated Vaccines
Contains a weakened version of the pathogen. It is not able to proliferate and spread throughout the body to cause sickness while still exposing the immune system to the antigen required to defend against the real pathogen. These are the closest thing to the pathogen out of all the vaccines. Live attenuated vaccines are safe for anyone with an uncompromised immune system but may result in symptoms after vaccination. Live attenuated vaccines need to be refrigerated to maintain its efficacy before administration.
Conjugate Vaccines
Some Bacteria infiltrate an untrained, usually young person’s immune system using a polysaccharide cover on its antigen. To combat this, vaccines are made using an antigen your body is familiar with that has a polysaccharide cover. Your immune system then links the polysaccharide to the antigen, eliciting an immune response when the polysaccharide itself is recognized.
Inactivated Vaccine
The infectious microorganism is killed with heat, leaving behind the antigen without the pathogenic agent. These do not need to be refrigerated and are less likely to have side effects than live attenuated vaccines but are less effective and need multiple doses to maintain efficacy.
mRNA Vaccine for COVID-19
The mRNA vaccine contains a modified messenger RNA which codes for the COVID-19 antigen. The mRNA is broken down immediately after translation leaving you with the specific immune response. The vaccine is created by taking the antigen DNA sequence to produce the mRNA is inserted into a plasmid vector, which replicates exponentially for several cycles before it is purified and finally encased in a lipid “shell”. Unfortunately, as we all know, the side effects from the vaccine can be quite unpleasant and the vaccine need to be stored at below freezing temperature to avoid degrading the mRNA. With this new breakthrough in vaccine technology, mRNA vaccines could be used to make a cheap, quick alternative to any vaccine that uses a protein-based antigen.
References
Centers for Disease Control and Prevention. (2018, August 17). Understanding how vaccines work. Centers for Disease Control and Prevention. Retrieved March 30, 2022, from https://www.cdc.gov/vaccines/hcp/conversations/understanding-vacc-work.html
Iwasaki, A., & Omer, S. B. (2020). Why and how vaccines work. Cell, 183(2), 290–295. https://doi.org/10.1016/j.cell.2020.09.040
Writers, S. (2019, November 22). How vaccines work. PublicHealth.org. Retrieved March 30, 2022, from https://www.publichealth.org/public-awareness/understanding-vaccines/vaccines-work/
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