There have always been people against vaccinations, but recently there has been an increased amount of anti-vaxxer parents voicing their opinions. This endangers not only their children, but other children and even other adults. Recently there was an outbreak of measles at Disneyland, when measles was considered eliminated from the United States before this.
First, vaccines are safe for the vast majority of people. The people who should not receive vaccines are people with compromised immune systems. Some people have allergic reactions to vaccines, but reactions are the reason doctors make people stay for a certain period of time after receiving the vaccine, and those who have reactions receive immediate care.
Other than those two reasons, vaccines are completely safe. The mercury in the vaccines is in such small amounts that it isn't harmful. Many of the pathogens that cause diseases are inactive in the vaccines, so they will not cause the disease. They also do not cause autism, and the person who wrote the research paper saying that it did, has his medical license revoked. In fact, not getting a vaccine is more dangerous than getting one.
Not only can an unvaccinated child get any disease that isn't eradicated, they can also spread that disease to the people who cannot get the vaccine due to a compromised immune system, or even other vaccinated children. The prevention rate for vaccines is high, but not 100 percent. The biggest reason diseases such as measles and mumps don't affect many children anymore is because so many children are vaccinated against it.
When the one healthy child who isn't vaccinated gets the disease, it puts the entire population at a higher risk of infection. It isn't fair to the child who isn't vaccinated, who has no choice in the matter, or other children who are around the unvaccinated child at school to be exposed to preventable deadly diseases.
It's great to do research on issues, but both sides of the matter should be researched before making decisions that can end in a child's death.