Whooping cough, a disease thought mostly eradicated by modern medicine, is making a comeback as the vaccine millions got to stave off the illness loses its effectiveness.
So far this year there have been nearly 18,000 cases of whooping cough, also called pertussis, reported in the U.S., and the number of cases could rise to 40,000 by year's end, the Washington Post reports.
The U.S. hasn't seen that many cases of whooping cough since 1959, the Post reports.
In Connecticut, the number of reported cases of whooping cough is rising dramatically this year, more than double the number of all cases in 2011, according to the Centers for Disease Control in Atlanta.
Data released by the CDC show that Connecticut in 2011 reported 30 cases of whooping cough. So far this year state health officials have reported 76 cases of pertussis.
Though generally not fatal to adults and older children, infants are particularly vulnerable to the disease, which can be fatal to children under the age of 1.
The CDC website on pertussis says it is marked by "uncontrollable, violent coughing which often makes it hard to breathe. After fits of many coughs, someone with pertussis often needs to take deep breaths which result in a 'whooping' sound."
Federal health officials are encouraging booster shots for those who have been vaccinated against whooping cough.
