Changes

While vaccines have been successful at preventing infectious disease, they have also resulted in controversy regarding their safety and effectiveness, legal and ethical issues surrounding mandatory vaccination, and whether children should be vaccinated against STDs<ref>https://www.historyofvaccines.org/content/articles/ethical-issues-and-vaccines</ref><ref>https://www.nvic.org/NVIC-Vaccine-News/January-2018/are-vaccine-ingredients-safe.aspx</ref>

While vaccines have been successful at preventing infectious disease, they have also resulted in controversy regarding their safety and effectiveness, legal and ethical issues surrounding mandatory vaccination, and whether children should be vaccinated against STDs<ref>https://www.historyofvaccines.org/content/articles/ethical-issues-and-vaccines</ref><ref>https://www.nvic.org/NVIC-Vaccine-News/January-2018/are-vaccine-ingredients-safe.aspx</ref>

There are five major types of vaccines and they are differentiated by what type of antigen is used. Live attenuated vaccines are created from the actual disease in question, however before injection the [[pathogen]] is [[attenuated]] (weakened) by growing successive generations of the pathogen in poor nutrient conditions. Because they contain live pathogens, it is still possible for these vaccines to cause infection, particularly in imunnocompromised individuals. Inactivated vaccines are created from pathogens that have been killed, usually with [[formaldehyde]]. Toxoid vaccines are created by using toxins produced by the pathogen, these toxins are exposed to heat and/or chemicals such as formaldehyde to inactivate the toxins, but [[antibodies]] that are produced to these deactivated toxins will also protect against the real toxin. Subunit vaccines use pieces of the pathogen in the vaccine. These pieces often consist of unique protein segments that stimulate the production of antibodies. Finally, conjugate vaccines protect against bacteria that are encapsulated in  polysaccharides (complex sugars), which disguise the bacteria, making it hard for the immune system to recognize them. Conjugate vaccines overcome this by attaching the sugar to a protein the does stimulate the immune system, thus triggering the immune system to react to the sugar in the future even if it is not accompanied by the protein.<ref>https://www.cdc.gov/vaccines/hcp/conversations/downloads/vacsafe-understand-color-office.pdf</ref>

There are five major types of vaccines and they are differentiated by what type of antigen is used. Live attenuated vaccines are created from the actual disease in question, however before injection the [[pathogen]] is [[attenuated]] (weakened) by growing successive generations of the pathogen in poor nutrient conditions. Because they contain live pathogens, it is still possible for these vaccines to cause infection, particularly in imunnocompromised individuals. Inactivated vaccines are created from pathogens that have been killed, usually with [[formaldehyde]]. Toxoid vaccines are created by using toxins produced by the pathogen, these toxins are exposed to heat and/or chemicals such as formaldehyde to inactivate the toxins, but [[antibodies]] that are produced to these deactivated toxins will also protect against the real toxin. Subunit vaccines use pieces of the pathogen in the vaccine. These pieces often consist of unique protein segments that stimulate the production of antibodies. Finally, conjugate vaccines protect against bacteria that are encapsulated in  polysaccharides (complex sugars), which disguise the bacteria, making it hard for the immune system to recognize them. Conjugate vaccines overcome this by attaching the sugar to a protein the does stimulate the immune system, thus triggering the immune system to react to the sugar in the future even if it is not accompanied by the protein.<ref>https://www.cdc.gov/vaccines/hcp/conversations/downloads/vacsafe-understand-color-office.pdf</ref>