Activists who dispute safety of vaccines are pushing to limit immunization requirements in schools

As South Carolina grapples with a measles outbreak that has infected nearly 1,000 people, groups with ties to the US health secretary, Robert F Kennedy Jr, are pushing to eliminate immunization requirements that protect children.

Activists are targeting vaccine mandates in states trying to tamp down measles as communities across the country struggle to stop the worst spread of the illness since the early 1990s. The Guardian found anti-vaccine groups are encouraging their followers to organize opposition to vaccine mandates in more than 20 states, including at least six with current measles outbreaks.