Vaccines undergo extensive testing
Before any vaccine is sold, it must pass a set of stringent safety tests.
Vaccines are the safer option when confronted with a choice between leaving a child vulnerable to disease or vaccinating them.
Among communities that face infectious diseases on a daily basis, where the benefits of vaccines are most visible, there are fewer fears over vaccine safety. This is because, relatively speaking, vaccines are "safe". The risks of not being vaccinated far outweigh the risks of being vaccinated. When we deal with medication and treatment, relative safety should be the only thing that matters.
The fiercest sceptics of vaccine safety are from the higher-income countries of Western Europe and North America. This is because these populations do not have to face the deadly consequences of the infectious diseases that ravage places like Bangladesh and Rwanda, where there is almost unanimous support and trust of vaccinations.  The only reason the safety of vaccines is widely discussed is because people in the West have not directly experienced the horrors of whooping cough or polio. Vaccines, even if they are not perfect, are far safer than leaving children exposed to these diseases.
Enter the counter arguments here ...
[P1] Vaccinating a child is safer than leaving it vulnerable to a deadly disease. [P2] Therefore, relatively speaking, vaccines are safe.
Enter the technical rejections of the premises here ...