Associated Press

LANSING — The Michigan Department of Health and Human Services says preliminary numbers show chickenpox cases were up this year through April compared with last year.

In a news release Wednesday, the department said preliminary figures indicate there have been 239 chickenpox cases through April, up roughly 57 percent from the same point in 2015.

The department says parents should make sure that kids are current on chickenpox vaccination. Department chief medical executive Dr. Eden Wells said in the release that "illness from chickenpox can be severe and sometimes require hospitalization resulting in serious complications."

In the majority of the cases this year, individuals had not been vaccinated. Nearly all of the outbreak-related cases had not been vaccinated.

Wells said the vaccine for chickenpox "is safe and very effective."

According to the Centers for Disease Control and Prevention (CDC), studies have shown the recommended 2-dose series given in childhood is somewhere between 89 percent and 98 percent effective in preventing any mild-to-moderate chickenpox disease and 100 percent effective in preventing severe chickenpox.

Unvaccinated kids lead to 57% spike in Michigan chickenpox cases