The anti-vaccine movement had grown in popularity even before the Covid pandemic. But murky guidance on the measles-mumps-rubella vaccine from Health and Human Services Secretary Robert F. Kennedy, Jr., did not help, experts note.

“This is a very clear example of the damage that the anti-vaccine movement has done in the United States,” Fiona Havers, an adjunct associate professor at the Emory School of Medicine and a former infectious disease staffer at the Centers for Disease Control and Prevention, recently told The Hill.

“There are a number of things that have made these ongoing outbreaks very difficult to control. One is that the decades of false information about measles vaccines that [Kennedy Jr.] and other people in the anti-vaccine movement have been spreading has led to a decline in vaccination rates,” she alleged.

“The U.S.’s political position in relation to health and vaccination is an outrage,” Rosana Richtmann, an infectious disease doctor and coordinator of the Brazilian Society of Infectious Disease’s immunization committee, told The Guardian in October, discussing the continent-wide measles surge. “It’s a problem for us.”