(NewsNation) — An infectious disease doctor is raising alarms about the outbreak of measles across the country, saying the disease is being driven by the anti-vaccine movement. 

Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security at the Bloomberg School of Public Health, said on “NewsNation Now” Monday it’s no surprise lower rates of vaccinations coupled with a highly contagious disease would lead to outbreaks. 

“We have to expect this to happen because there are many parts of the world where measles is not controlled, and our control in the United States is completely premised on having high vaccination rates, and those have been slipping,” Adalja said.

He attributes this slip in vaccine rates to an anti-vaccine movement that became highly prominent during the COVID-19 pandemic. 

“What’s dangerous now is this is being really revved up by the anti-vaccine movement, and we’re seeing more and more schools have more and more [vaccine] exemptions,” he said. “This is a really robust vaccine that’s been tried and true for so long, so it’s really mind-boggling that people have turned against it.”

According to the Centers for Disease Control, 17 states have reported 45 measles cases this year so far. There were 58 cases in the entire year in 2023. 

Two cases of measles were reported at a migrant shelter in Chicago in the last few days, with health officials warning it could lead to a larger outbreak as many asylum seekers are unvaccinated.

The first case marked the first occurrence in five years in Chicago, the health department said.

In the Sacramento area, a child tested positive for measles this past week, potentially exposing more than 300 people, according to El Dorado County Health officials.

“Measles can actually erase part of your immune system. You become more susceptible to other infections because measles can alter your immunity to other things that you may come into contact with,” Adalja told NewsNation. “Measles has this long tail.”

Adalja particularly cautioned parents of unvaccinated children, noting the hospitalization rate is one in five children.

With fewer kids being vaccinated due to misinformation being spread by the anti-vaccine movement, there will be “more cases, more disruptions, more schools getting impacted more, more public health investigations and isolation and quarantine of these individuals,” Adalja said. 

“This is all preventable, and all the costs that are going to be incurred are preventable costs,” he said.