Dozens of children have contracted measles in the state’s largest outbreak in 33 years. Online, some are blaming vaccines for the disease’s spread.

Amid one of the largest measles outbreaks in the United States in nearly a decade, anti-vaccine activists are promoting false claims that shots are ineffective in stemming the spread of the virus or that they could cause the disease.

After being declared eradicated 25 years ago, measles is making a comeback. The good news is, most people who were vaccinated have good protection. Throughout February, a measles outbreak has been growing in West Texas.