Minnesota so far has escaped measles infections at a time when the country has seen more than 700 cases, the highest number in the past 25 years. But health officials here know that the seeds of an outbreak could be just a plane ride away.
The highly infectious disease is resurgent globally, and travelers from other countries have sparked 13 outbreaks and a scattering of isolated cases across 22 states, including Michigan, New York and California.
Measles was declared eliminated in the United States in 2000 by the Pan American Health Organization, meaning that an outbreak can't start until an infected person imports the virus and spreads it to those who lack immunity.
That's what happened here in 2017, when a measles outbreak sickened 75, including many in the Somali-American community, where just 40% of young children had received the measles, mumps and rubella (MMR) vaccine.
Although many parents chose to get the shot for their children during the outbreak, recent tracking data indicate that measles vaccination rates have dropped to pre-outbreak levels for kids aged 24 to 36 months among Somali-Americans.
"We definitely have a way to go to make sure the community is fully vaccinated," said Kris Ehresmann, infectious disease director at the Minnesota Department of Health.
But officials are also concerned about other low-vaccination populations. A recent Star Tribune analysis of school immunization records found that one-third of Minnesota schools had kindergarten vaccination rates below the level required to prevent outbreaks for measles and chickenpox.
"We have a lot of pockets of concern," said Patsy Stinchfield, senior director of infection control at Children's Minnesota.
The nationwide outbreaks, though, are raising concerns and questions, especially among those who have no firsthand experience with a disease that largely had been eradicated in the United States.
"We are hearing from parents wanting to check their child's immunization status," said Stinchfield.
Some parents are wondering what they should do before traveling with children younger than 12 months, the recommended age for the first of two doses of the measles vaccine.
"If people are traveling, a first dose can be given as early as 6 months of age," Stinchfield said. But the child would still need the standard two-dose round after reaching age 1.
The U.S. Centers for Disease Control and Prevention in Atlanta said travel is not recommended for anyone who lacks measles immunity.
Studies have shown that the measles virus can linger in the air for up to two hours after an infected person leaves an indoor space.
"People are concerned about airports, and I think that is a reasonable concern," said Stinchfield.
New York City has one of the largest outbreaks, with 423 cases mostly in Orthodox Jewish communities. There is also a large outbreak in Israel. During the Passover holiday, when many travel to be with family, local Orthodox Jews took precautions, said Rabbi Yehuda Shurpin of Chabad Shul in St. Louis Park.
"I am aware of many in the community who made sure to ascertain that everyone was up to date with their vaccines and also tried to get early boosters for young children who ordinarily may have gotten them when they were a bit older," Shurpin said.
Very few religions advise against vaccines, and leaders of communities with low vaccination rates have tried to encourage parents to give their children the MMR shots to keep the community healthy.
But in some cases, worries about the disproved link between the MMR and autism persist.
Focus groups conducted by the Wilder Foundation for the Star Tribune in 2017 found Somali parents who fear autism more than measles. Many felt besieged and pressured during the outbreak, complaining that health authorities didn't take the time to listen to their concerns.
Several parents said that once their children had gotten older and showed no signs of autism, they would then allow them to get the MMR vaccine.
"Our first job is to listen and find out what is motivating their fear," said Stinchfield. "We talk about what we know about autism and what we don't know about autism."
Studies increasingly point to a genetic basis for the autism spectrum, she said, and autism develops much earlier than when the first MMR shot is given.
Dr. Peter Hotez, a vaccine advocate and dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, said health leaders need to do a better job of responding to false information about vaccines.
"The sense I get is that the majority of parents are not deeply dug in," said Hotez. "They've been besieged by antivaccine misinformation and there has been nobody to tell them otherwise."