Since the discovery of the first vaccine in 1796, thousands of lives have been saved. Diseases such as Smallpox which claimed millions of lives during the middle ages are no longer a threat to human beings. The following are the different types of vaccines you should know.
Various types of vaccines
This involves introducing weakened live bacteria or viruses in the body. Even though these microbes are not capable of causing disease, they trigger a counter-reaction from the immune system. This will strengthen the body’s line of defense and will protect a person from contacting the disease in case of future attack. Attenuated vaccines are closely interpreted as a natural infection and spur a strong antibody reaction guaranteeing lifelong immunity.
However, because they involve the use of live microbes, there is a chance albeit a slim one that they may mutate or change to become active again. If this was to happen, it could lead to a serious bout of the disease. For this reason, these vaccines are not suitable for people with a weakened immune system such as people carrying the AIDS virus or people who are undergoing chemotherapy. Some of the common vaccines here include measles, smallpox, and yellow fever.
Instead of introducing live microbes into the body, these vaccines involve the use of inactivated or killed pathogens. Just like with live bacteria or viruses, inactivated microbes can still spur a defense reaction from the immune system. However, this reaction is milder as the body does not recognize them as a serious threat. As a result, they do not offer protection for a long period. Because the microbes used are inactive, they cannot become disease-causing making them safer for people with poor immune systems. The common types of this vaccine include the flu shot and polio vaccine.
Some bacteria cause diseases by releasing harmful chemicals or toxins. Such bacteria include Corynebacterium diphtheria and Clostridium tetani that are responsible for diphtheria and tetanus. This vaccine involves introducing into the body inactivated toxins similar to those caused by the actual bacteria but lacking in potency. As in the case, with inactivated vaccine, toxoid vaccines trigger an antibody response that helps the body fight a future attack.
These are made by combining an antigen to a bacteria coating to make it more discoverable by the body’s immune system. Many harmful bacteria possess an outer coating made of complex sugars called polysaccharides. Such coatings hide bacteria’s antigens and allow them to multiply in the body without being detected by the immune system. This is especially possible in infants and young children whose immune system is immature. Conjugate vaccines link a discoverable antigen from a microbe to the polysaccharide triggering a counter reaction from the immune system which helps the body to be prepared for such disease-causing organisms in future.
This is a highly specific process that involves separation of antigens to include only the one that triggers the best counter reaction from the immune system. Subunit vaccines, therefore, omit unnecessary molecules from the microbes reducing the chances of adverse reactions. These types of vaccines are used for protection against diseases such as meningitis and Hepatitis B.