Immunization is one of the most important public health achievements in human history. Vaccines helped eradicate smallpox globally and eliminate polio in the United States. The introduction of effective vaccines has also drastically reduced deaths from measles, diphtheria, rubella, pertussis (“whooping cough”) and other diseases that sickened hundreds of thousands of Americans in the early 20th century.

But as long as there have been vaccines, there has been opposition and, at times, misinformation campaigns that threaten the achievements that have been made. Worries about a discredited link between vaccines and autism and unfounded fears about the quantity of childhood vaccines have caused a small group of parents in recent years to decide against immunizing their children. This leaves children vulnerable to measles and other potentially lethal viruses that should be relegated to the history books.

In 2014, the Centers for Disease Control and Prevention recorded 667 cases of measles in the United States, up from just 55 in 2012.