Cara Hathaway left her job as a speech therapist because she couldn’t work in a hospital and speak out against the vaccine manufacturers she believes are doing more harm than good, she said.

A bad reaction to the vaccine for human papillomavirus and a miscarriage after she was vaccinated for the flu motivated Hathaway to learn more about what has become a heated national debate over whether vaccinations should be required for schoolchildren and adults in some workplaces.

Public health experts and the federal Centers for Disease Control and Prevention are clear: vaccines are safe and effective. Still, fears of side effects and chronic illness have stoked a vocal anti-vaccination movement that came to the Ohio Statehouse on Wednesday.

About 120 activists, many of them wearing red, listened in the atrium as a panel of speakers described the ways they believe regulators and pharmaceutical companies are hiding the truth about damage caused by vaccines.