Cases of whooping cough, also known as pertussis, keep rising in the Unites States, health officials inform.

Starting Oct. 22, 25 whooping cough cases have been reported in the Clermont County district. 22 elementary students, two middle school students, as well as one teacher have fallen ill. As investigations continue, more and more students are sent home. However, the situation isn’t alarming, according to Clermont County Health Commissioner Marty Lambert, who says what is currently happening is not unusual.

Although the disease is relatively rare, since it is a highly contagious one, it is very easy to catch it. According to public health officials, it is very likely to see a spike in whooping cough cases every three to five years. "It's direct respiratory droplets from person to person," said Cindy Hosking, nurse at the Noblesville Schools and the district's school nurse coordinator.

Whooping cough cases are on the rise across Missouri, in Wisconsin County, Angels Camp, Marion County, Hudson and not only. A recent study suggests that almost 1 million cases could be annually prevented by regularly vaccinating youngsters and adults against the respiratory illness. Whooping cough is the most common vaccine-preventable disease among U.S. children under 5 years of age.

The current outbreak started among students that weren’t immunized at Estes Hills Elementary School in Chapel Hill, North Carolina.