When physicist Neil Johnson moved to Maryland in 2018 to take a job at George Washington University (GW), he looked online to see what medical requirements his son would have to meet before entering high school. He quickly stumbled upon many parents having online conversations about tactics they could use to get out of vaccinations — something that had never crossed his mind.
A year later, the U.S. experienced its biggest measles outbreak in almost three decades, with the majority of cases involving people who hadn’t been vaccinated. Johnson — who had, since 2014, been applying tools from physics and math to study the online behavior of terrorist and hate groups — suspected that something interesting, and unsettling, was happening on the web to shape attitudes toward vaccines and advice from the medical establishment in general.
