Riots in recent American history seem to be thought of largely as a 60's phenomenon, but mob mentality and action have of course been around for as long as people have gathered. Take the 1904 Brazilian Vaccine Revolt, which demonstrated that today's vaccine paranoia is nothing new:
In an effort to eradicate smallpox in the city, the government passed the Mandatory Vaccination Law, which gave medical personnel and police the right to enter and citizen’s home and administer smallpox vaccinations by force, if necessary ... Citizens, angry at their homes being invades or destroyed, and fueled by rumors about the dangers and depravity of the vaccine (it was rumored women had to undress to be vaccinated), rioted for 6 days in November. They looted shops, started fires, built barricades, attacked government employees and military forces with rocks and debris, and destroyed trains and tracks.
From the Upcoming ueue, submitted by redsfaithful.