Types of Vaccines
By: Arushi Dhingra
In today’s world, there are several types of vaccines. Each and everyone’s structure is different but has the same goal: fight off germs and the diseases they can cause. When scientists make vaccines they take into account three main things. First, how will the immune system respond to the germ? Second, what type of population does the disease affect, and therefore, who needs to be vaccinated? And finally, what is the best technology to tackle the disease and create a vaccine?
Taking into account these three questions, scientists have created 4 main groups of vaccines. The first is live-attenuated vaccines. Live vaccines use a weakened (or attenuated) form of the germ that causes a disease. Because these vaccines are so similar to the natural infection that they help prevent, they create a strong and long-lasting immune response. Just 1 or 2 doses of most live vaccines can give one a lifetime of protection against a germ. However, live vaccines have some limitations. Because the vaccine carries a low dose of the virus, people with weakened immune systems or people who have had an organ transplant can be put at risk. Live vaccines also need to be kept cool which prevents them from traveling easily. These live vaccines protect against measles, mumps, rubella, rotavirus, smallpox, chickenpox, and yellow fever.
The second type of vaccine is an inactivated vaccine. These use the “killed” version of the germ that causes the disease. Inactivated vaccines are much weaker than live vaccines so they require “booster shots” to prevent getting the disease. These vaccines are used to protect against hepatitis A, the flu, polio, and rabies.
The third classification of vaccines are subunit, recombinant, polysaccharide, and conjugate vaccines that use specific pieces of the germ like the protein, or sugar. Because this vaccine only uses specific parts of the virus, they only give a strong immune response to the key parts of the germ. This is usually used on people with weaker immune systems. However, these also require additional shots to get continuous protection. These vaccines are commonly used to combat HIB disease, hepatitis B, HPV (Human papillomavirus), whooping cough, pneumococcal disease, meningococcal disease, and shingles.
Finally, the fourth type of vaccine is known as toxoid vaccines. Toxoid vaccines use a toxin made by the disease-causing germ. This creates immunity to the parts of a germ instead of the germ as a whole. These also need booster shots. Toxoid vaccines are used to protect against diphtheria and tetanus.
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“Vaccine Types.” National Institute of Allergy and Infectious Diseases, U.S. Department of Health and Human Services, www.niaid.nih.gov/research/vaccine-types.
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