followingvaccinations.comは安全ですか？

There is no useful content here at all. It is just a list of unsubstantiated stories purporting to be from parents of vaccine injured children. There is no third party corroboration of any of the reports to confirm their veracity. No reports from doctors confirming that these children had the claimed health problems. No medical records showing that they didn't have any other risks factors from disease. Not even a media story to even document that these children even exist. Given the general lack of evidence it is safe assumption that this site accepts any reports that people send their way. They also have links on their page to a number of questionable websites such Mercola.com, Whale.to, the Australian Vaccination Network, and vaxtruth.org.