Amid a spike in measles outbreaks around the world, a group of health care workers in New York have decided to promote their own pro-vaccine stance using custom-made t-shirts, USA Today reports.

The staff from Legacy Pediatrics in Rochester, New York, created shirts that read “Vaccines Cause Adults” and shared a photo of themselves wearing them on Facebook. The shirts are meant to get the message across that vaccines are essential and do not cause autism, a theory that is often suggested by anti-vaxxers.

“We have to be as loud and as emphatic as the anti-vaxxers and unfortunately it’s not very sexy or headline-grabbing to say that vaccinations are safe and effective,” Dr. Janet Casey told USA Today. “I'm real proud of us.”

Take Action: Encourage South Africans to Prioritize Child Health and #VaxTheNation

Aside from there being no scientific evidence linking vaccines to autism, the idea that a parent would rather expose their child to a life-threatening and preventable illness than have an autistic child is offensive, advocates explain.  

Measles cases tripled between 2017 and 2018 in Europe. The Philippines and Madagascar are currently experiencing deadly outbreaks of the virus and Washington State has had to declare a public health emergency amid an outbreak there. Cases have since popped up in Canada, too.

A recent report by the Centers for Disease Control and Prevention suggested that the anti-vaccination movement was to blame for the uptick in outbreaks. Doctors have recently noted that unvaccinated teens have been going to clinics to get vaccinated, despite their parents' views.

Every year, more than 100,000 people die from measles, most of which are children under the age of 5, many living in the world’s poorest countries. Vaccination is essential in preventing outbreaks and ultimately deaths associated with the virus.

Casey and her t-shirt crew’s message is clear: Vaccines save lives. Crazy Dog T-Shirts provided the shirts for free and the office has sold 30 shirts so far, according to USA Today.

“I’m pleased with how much vaccination proponents are speaking out right now since we’ve had these measles outbreaks,” Casey said. “I thought for a long time it would take a diphtheria (a rare bacterial disease) or polio to return and a couple hundred people to die for people to say, wait a minute — this is unacceptable. Maybe we don’t have to get to that point.”