ST. PAUL — Minnesota health officials said there’s an increase in the number of chickenpox cases this year.

Department of Health spokesman Doug Schultz said nearly 400 cases have been reported, the highest number since 2013 when about 480 cases were reported.

Schultz said there’s an outbreak of 15 cases in one Hennepin County school and another six cases in Stearns County.

He said that outbreaks typically happen in private or charter schools where there’s a higher percentage of unvaccinated children. Unlike the flu, Schultz said the chickenpox is not a seasonal illness and can happen throughout the year.