There are different types of vaccines but they share similar objective which is to teach the immune system how to fight off certain type of bacteria or virus. There are several types of vaccine for example inactivated vaccines, live-attenuated vaccines, messenger RNA (mRNA) vaccines and others.
Inactivated vaccines use the killed version of the bacteria or virus that caused the disease. However, inactivated vaccines usually do not provide strong immunity when compared to live vaccines. Thus, several doses over time is required to obtain immunity against the particular disease. Example of inactivated vaccines includes Hepatitis A, Polio, Rabies and others.
The second type of vaccine is live-attenuated vaccines. Live vaccines use the weakened version of bacteria or virus that cause the disease. Since these vaccines are similar to the natural infection, they can provide a very strong and long-lasting immunity response. The con of live-attenuated vaccines is not suitable for every individual as it contains live pathogen which will harms individual with weakened immunity system, long-term health problems or people that just received organ transplant.
The third type of vaccine is mRNA vaccines, which is used to protect individual against Covid-19. mRNA vaccines contain genetic material mRNA inside a special coating that encodes the viral protein. When these genetic materials are injected, the cells will translate them and produce viral protein directly in the body. This mimics what Covid-19 does in nature, however the vaccine mRNA only codes for the critical fragment of the viral protein. This gives the immune system a preview of the real virus without causing disease. This will allow immune system to design powerful antibodies to fight off real virus.
