Pertussis spreads through Kansas county

Twenty-one new cases of whooping cough, also known as pertussis, have been reported in Johnson County, Kansas, in the past week, bringing the total number of confirmed cases of the disease to 111.

The public health department in Johnson County issued a warning about the pertussis outbreak, urging residents to get the vaccine and to be aware of symptoms to halt the spread of the disease. The number of cases are substantially up from last year, when the county only received 11 probable, suspected and laboratory confirmed cases, the Kansas City Star reports.

"This is a problem that Johnson County is sharing with Americans all across the country," William Schaffner, an infectious disease specialist, said, according to the Kansas City Star.

More outbreaks have occurred in the last few years as parents have become skeptical of vaccines. In addition, the effectiveness of the pertussis vaccine can diminish over time and most adults don't realize they may need a booster shot.

Most of the cases in the county have affected people in fifth through eighth grade. The most vulnerable to the disease are the elderly, toddlers and infants. Approximately half of infants with pertussis are hospitalized and one in 100 will die, according to the Centers for Disease Control and Prevention.