Vaccines save 2–3 million lives each year, according to the World Health Organization. But misinformation abounds. Cedars-Sinai pediatrician Kyle Monk, MD, offers some fast facts to help keep you, your family and your community protected.

Vaccines are rigorously tested for safety and continuously reevaluated and monitored for side effects. “The biggest fear comes from false ­information from internet ‘sources’ that correlate vaccines with autism,” Monk says. “The doctor who wrote the original article making this claim lost his license, and others who backed him have retracted their support.”

“Vaccines are one of the most important ­inventions of modern medicine,” Monk says. “I’ve seen parents watch their child die and realize they could have prevented it.”

Children’s immune systems are not as strong as adults’ immune systems. “Vaccines are a killed portion of the bacteria or virus that we introduce to the immune system,” Monk says. “It’s how the immune system learns to fight that infection later in life.”

Without immunizations, long-vanquished infectious diseases will quickly reappear in the U.S. “No matter where you live, the reality is that you’re going to come into contact with people from all over the world, and you will be exposed to a virus,” Monk notes.

By the end of August 2019, 1,234 cases of ­measles were reported in 31 states—the largest U.S. outbreak of this highly infectious disease since 1992, according to the Centers for Disease Control and Prevention. “Vaccines are the most important safety recommendation I give to my patients—and that certainly includes vaccination for measles,” Monk says.