Some of the students initially believed vaccines and autism were linked, they said, but changed their minds as they researched.
Complaints began to arise when a local newspaper reported that the students were tackling "the issue of immunizations."
A blogger who saw the article contended that the movie, still a work in progress, was sure to be "propaganda." That led to a flurry of frightening phone calls and Internet comments directed at CHSTV, [parent adviser Lisa] Posard said.
Posard said she hadn't realized that vaccines were such a controversial subject. She and CHSTV teacher Douglas Green wanted to shut down production, she added. But the students, angered by what they saw as bullying, insisted on completing the film.
The final version of "Invisible Threat," completed in spring 2013 but shown only to select audiences, took a strong pro-vaccine position.
Critics, who said they hadn't been allowed to see the movie, leaped back into action about a year later, when the film was set to be screened on Capitol Hill.
Focus Autism and AutismOne organizations complained about the movie's Rotary Club backing and about the involvement of Dr. Paul Offit, a University of Pennsylvania pediatrician and immunization proponent. They argued that "Invisible Threat" was "scripted with industry talking points" and that the movie seemed to be the work of adults operating under false pretenses, not students.