The immunization rate against measles among D.C. schoolchildren is lower than experts say is ideal. And with a nationwide measles outbreak spreading, city officials are telling parents to get their kids vaccinated before the school year starts.

D.C.’s immunization rate is 91 percent, which can put the city at risk, said D.C. Department of Health Director LaQuandra Nesbitt at a press conference Monday.

“We know that it’s more than likely we can have an outbreak that spreads very quickly if our rates are below 95 percent,” Nesbitt said. “What we benefit from — called herd immunity — goes away when we’re below 95 percent. So we all need to band together and have our children vaccinated so that we can get those rates back up above 95%.”

Nationwide, there have been 1,123 cases of measles reported in 28 states — the worst such flare-up since 1992. While no cases have been reported in D.C., there have been cases in Virginia, Maryland and Pennsylvania.

“Where do people in the District in our daytime population come from? Maryland and Virginia,” Nesbitt said.

According to the Centers for Disease Control and Prevention, the historic rate of measles vaccinations through 2017 in Maryland was 92.4 percent and 97.6 percent in Virginia.

Under D.C. law, any student entering school — public, private or parochial — has to be vaccinated against a range of diseases, including measles, polio, chickenpox, and hepatitis A and B. Like in 45 states, parents in D.C. can receive an exemption if they can demonstrate a religious objection to vaccines.

According to the D.C. Health Department, roughly 93 percent of students attending traditional public and public charter schools have been vaccinated against measles, with the numbers dropping slightly in private (91.9 percent) and parochial (87.2 percent). Overall compliance with all required immunizations is lower, though, ranging from three-quarters of students at public schools to only half at parochial schools.

While there have been cases in other parts of the country where parents have opted against certain vaccines because of unproven claims that they could be harmful to a child, health officials in D.C. say a more likely reason for the city’s lower-than-ideal immunization rates is poverty.

On Monday, D.C. officials said that residents on Medicaid could get free immunizations at any of 42 community health centers located across the city. For everyone else, they urged them to work through their primary-care physician to get caught up on all vaccines.

“The creation of something like vaccines over 100 years has done more to extend lives than some of the modern technologies that we often celebrate and chase and try and get for our families,” Nesbitt said. “Vaccines save lives. They are safe, they are effective.”

Students entering sixth grade are also required to get the HPV vaccine, though parents can choose to opt out. As of January 2019, roughly 65 percent of students in public, charter and private schools had gotten that vaccine, while 45 percent at parochial schools had done the same.

As measles cases started spiking earlier this year, Ward 3 Councilmember Mary Cheh introduced a bill that would allow any minor in the city to get a vaccination if they wish, doing away with the city’s existing law that requires parental consent for vaccinations until a child turns 18.

It has yet to get a hearing.

This story first appeared on WAMU.