Minnesota has declared a hepatitis A virus (HAV) outbreak, making it the 29th U.S. state to do so since 2016, Minneapolis’s Star Tribune reports.

Amid a nationwide battle against the virus, all but California’s and Utah’s are ongoing. More than 23,000 people across the country have gotten sick, and 233 have died. Until now, state health officials say Minnesota had been fairly shielded from the national outbreak, but a recent uptick in cases has some state officials concerned.

According to an announcement last week by the Minnesota Department of Health, 23 people have recently fallen ill with hepatitis A in the state. Thirteen of those patients required hospital care. 

With the declaration of an outbreak, Minnesota will unlock federal resources to address the crisis, including heightened access to the hepatitis A vaccine, which can prevent infections. In Minnesota, vaccination has been standard for children born in 2006 or later, but most teens and adults aren’t protected.

People who live in shelters or on the streets or are imprisoned are at an increased risk for infection, as are drug users. Initial cases appeared in East Central Minnesota and involved people who had contact with one another. Since then, cases have been reported in nine different counties. 

Health workers on the ground in Minnesota say they’re currently focusing their vaccination efforts on homeless populations and in local jails and prisons.

For more information about the hepatitis A vaccine and where to get it, click here.