Recent years have seen outbreaks in vaccine-preventable illnesses, including a current outbreak here in Washington state.
Topics like vaccination can bring up a lot of emotions. It's important to keep an open mind, but also to think critically.
Online articles or videos that use language full of emotion are not the best resources to inform yourself about any issue.
A great library resource for general information is Credo Reference. It has a topic page on Vaccination that explains the basics of what it is and how it works.
The library's Opposing Viewpoints database gives a good summary of issues surrounding vaccines and many other topics.
A lot of the fear surrounding vaccines has come from a flawed study linking them to autism that has since been retracted and refuted.
The truth is that there has been no proven link between vaccines and autism, but there are reasons why the belief in a link persists. A somewhat dense, but well-written article to understand those reasons is here:
However, although there is no proven link to autism, in rare cases vaccines may cause other adverse reactions in some individuals with allergies or otherwise compromised immune systems. The U. S. Department of Health and Human Services tracks these via the Vaccine Adverse Event Reporting System (VAERS).