How vaccines can protect everyone if enough people get them.

Vaccination and herd immunity have been hot topics for a while, but a recent surge in measles and other vaccine-preventable diseases in the United States has reignited debate. For some, it is a matter of freedom of choice. For others, it is a matter of social responsibility.

Most Americans have never seen diseases like measles or whooping cough. This is due to past generations’ commitment to vaccination, which gradually eradicated these diseases in the United States. Since the diseases are no longer an everyday danger, the anti-vaccination movement has been gaining traction. For some people, the perceived immediate threats of vaccinations are more frightening than the abstract threat of a disease they may never see.

In a recent study published in the journal Vaccine, researchers found that a sample of anti-vaccine commenters falls into four categories: people who don’t trust doctors, people who prefer alternative medicines, people who worry about vaccine safety, and conspiracy theorists. While this study is not comprehensive, it does describe some of the arguments made against vaccines by people who have not experienced large-scale disease outbreaks.

In our new globalized world, we are more likely than previous generations to run into people from countries where preventable diseases have not been stamped out. Even people who haven’t travelled can’t know where every other person they meet has been. This has led to outbreaks in the U.S. of previously eradicated diseases, like the measles found in Washington, Texas, and California.

This month we spoke with Ken Henderson, Senior Director of Laboratory Services at Charles River Labs. His perspective comes from the laboratory side, where it is crucial to protect research animals from infection. Protection in this sense comes not only from vaccination, but also from physical barriers, food and bedding sterilization, and quality control to prevent human error.

Ken and Mary discuss herd immunity, disease vectors on cruise ships, and disease resurgence. Listen now to this month’s episode of Eureka’s Sounds of Science.