Vaccines have been around for hundreds of years dating back to 1796 when Edward Jenner created the first smallpox vaccine. Jenner, an English country doctor, noticed cowpox, which were blisters that formed on the lips of female cows. Jenner then took the liquid from the cow's bladder and scratched it onto an eight-year-old boy. A single blister formed where the boy had been scratched, but it recovered quickly. After this experiment, Jenner injected the boy with smallpox matter. No illness occurred, the vaccine was a success. Doctors across Europe soon began to proceed with Jenner's method. Seven different vaccines came from the single experimental smallpox vaccine. Now questions were on the horizon. Should everyone get vaccinated? Where is the safety limit? How can they be improved? These questions needed answers, and a couple of centuries later, with all the technology, we would get them (ncbi.nlm.nih.gov). Since the smallpox vaccine was invented, over a hundred other vaccines have been created. Each vaccine created falls into one of seven vaccine types. One type is live or attenuated, meaning the vaccine contains a live virus that has been weakened or altered so that it does not cause disease. Attenuated vaccines are good “teachers” for the body because they are the closest thing to a natural infection. An example of an attenuated vaccine would be vaccination against measles, mumps, yellow fever or chickenpox. Attenuated vaccines can be produced in several ways. The most common method involves taking the virus and subjecting it to a series of chick embryos. When the virus passes through embryos it loses the ability to reproduce in human cells. The only downside to the attenuated vaccine is that it doesn't work with either paper or the bacterium used as a carrier. Recombinant vector vaccines are still being tested today, just like DNA vaccines. The only difference between recombinant vector vaccines and DNA vaccines is that recombinant vector vaccines use an attenuated virus or bacterium to introduce microbial DNA into the body's cells. Scientists created this vaccine by observing nature and how nature transmits viruses. Scientists have noticed that viruses in nature attach themselves to the cells they want to inject, which led scientists to figure out how to take parts of an attenuated virus and add genetic material from other microbes. I know it may sound confusing, but it's pretty simple. Think of it as virus poisoning. Recombinant vector vaccines come very close to mimicking a natural infection, which causes the immune system to become energized and activated sooner.