With state health officials reporting 31 cases so far this year, Kentucky is now the fifth state to declare a hepatitis A virus (HAV) outbreak in 2017, Food Safety News reports.

The state follows similar hepatitis A crises in California, Michigan, Colorado and Utah in which a total of 1,350 cases and 41 deaths have been reported. In California, about two thirds of confirmed victims have been homeless and/or people with substance use disorders. Cases in Michigan have followed a similar pattern. However, a number of victims in other outbreak states don’t fit into either category, suggesting that the outbreak is branching out from at-risk populations.

Kentucky health officials say they are working hard to vaccinate adults across the state, focusing on homeless people and substance users first. Of the 31 cases reported thus far, 19 have been in Jefferson County, which includes the populous city of Louisville. On average, Kentucky records 20 cases of hepatitis A per year, meaning that 2017 marks a 50 percent increase in new infections.

As all five states continue to contend with their crises, the country faces a hepatitis A vaccine shortage. In response, federal health officials have been working with state and local health departments over the past several months to help combat the various outbreaks more efficiently.

Thus far, test results match the genotype associated with the hepatitis A outbreaks in California, suggesting they are connected.