Vaccines are one of the best defenses we have against preventable and contagious diseases. Vaccines stimulate the body's immune system to fight off the future disease. However, as dependable as vaccines are, there still exist risks like other medical products. It might cause some side effects, such as redness, swelling, or soreness at the injection site. Some might cause fever, rash, and achiness. Although the side effects are usually really mild, people are still scared of the risk that may incur with incompatibility of the body and the vaccine. More severe side effects include blood in the urine, pneumonia, and inflammation of stomach or intestine, but it is not clear if these side effects happen because of the vaccine, or just by chance occur after vaccination. Nevertheless, without receiving vaccines more serious diseases can spread to the others. There is evidence that the increase in vaccine refusal and the geographic clustering of refusal increases the risk of disease outbreak. Thus, the safety and importance of vaccine is in need to be promoted.
Ever since vaccines first became required by law in 1809 for smallpox, it was proven that vaccines can help prevent disease outbreaks. Despite the effectiveness of the vaccine, in 1850 some irregular physician came up with unconventional medical theories which led to decrease usage of vaccine and ultimately caused the reappearance of smallpox. The reappearance further assured the efficacy of vaccine. According to Orenstein's research, it had always been difficult to enforce vaccination laws. In 1969, seventeen states had laws that required children to be vaccinated for measles before entering school, and twelve states enforced vaccination against all six diseases. Finally, in the 1980s, all 50 states acknowledged the importance and had school immunization requirements.
Nevertheless, there are considerable differences in immunization requirements around the country since the immunization laws are state-based.