The Kentucky Department for Public Health says more than a third of students haven’t received the mandated Hepatitis A vaccination.

The Lexington Herald-Leader reports immunization rates released Tuesday show about 65% of the 209,904 mandated students have received the shot. The state’s target compliance rate is 85%.

Results show seniors had the lowest compliance rate at 46% and kindergartners had the highest with 84.3%.

University of Kentucky infectious disease pediatrician Dr. Sean McTigue says the compliance lag is because of general hesitancy regarding vaccines and the need for two shots. McTigue believes it’ll take “at least two years” to get everyone onboard.

Kentucky experienced a Hepatitis A outbreak in 2017, prompting the mandated vaccination. As of September, the health department says 4,943 people are infected and 61 people have died.