The World Health Organization has a list of:

“Web sites that provide information on vaccine safety and that adhere to good information practices. While many quality web sites offer science-based information about vaccine safety, others may provide unbalanced and misleading information. This can lead to undue fears, particularly among parents and patients.”

A few examples among those above mentioned good information sources are:

UK National Health Service, NHS choices – How do I know vaccines are safe?

Australian National Center for Immunisation NCIRS, fact-sheets on vaccine preventable disease and vaccine safety.

The American Academy of Pediatrics (AAP) vaccination information site:

Many parents worry about the possible side effects of vaccinating their child and if their child really needs all those shots. Misinformation abounds on the Internet, making it hard to find a reliable source of information. Check below for expert answers on your top vaccine safety questions.

Chidren’s Hospital in Philadelphia Vaccine Education Center:

The disappearance of many childhood diseases has led some parents to question whether vaccines are still necessary. Further, a growing number of parents are concerned that vaccines may actually cause other diseases. Although unfounded, these concerns have caused some parents to delay vaccines or withhold them altogether from their children.

There is also: “The World Health Organization, Global Vaccine Safety: Six common misconceptions about immunization”

Or if you like it hard-core, go search for vaccine research on PubMed – the most extensive medical journal database there is. For instance, search for ‘vaccines’, then look to the left column and choose ‘Review’ under ‘Article types’. Crash course into vaccine science!