More pertussis cases in Minnesota in 2014

Minnesota saw more pertussis cases in 2014 than it did the year before, but the total was still smaller than recorded during a massive outbreak in 2012.

The highly contagious respiratory disease produces a severe cough that can last for up to three months. Pertussis is a bacterial disease, also known as whooping cough, and can be very serious — occasionally fatal, especially in infants.

As of Dec. 31, Minnesota had tallied 1,120 cases of pertussis during 2014, a jump of more than 80 cases from 2013.

Ten years ago, case counts exceeding 1,000 would have been considered remarkable, but now they're becoming the norm. A pertussis outbreak in 2012 sickened 4,639 people in Minnesota.

Public health officials say a modified version of the TDaP vaccine, introduced in the mid 1990s, does not appear to be as effective as an older version of the vaccine that had more side effects.