CEDAR RAPIDS, Iowa (AP) -

Linn County health officials are offering free booster shots to students as cases of whooping cough continue to rise locally and statewide.

The Gazette says the county health department is partnering with middle and high schools to provide as many free shots as possible to students 10 and older.

The Iowa Department of Public Health says 1,085 cases of whooping cough, or pertussis, have been reported in Iowa this year. That's up nearly 5 times the number reported in 2011.

There have been 178 cases in Linn County this year, by far the most in the state.

Whooping cough spreads through the air when an infected person coughs. It's a preventable infection through vaccination.