Whooping cough vaccine efficacy under study

Scientists and public health officials are studying a Vermont whooping cough epidemic to determine if the current vaccine is less effective against a new strain sweeping the country. The Centers for Disease Control and Prevention and the Vermont Health Department are examining the records of 854 people, ages 4 to 19, with confirmed or probable cases of pertussis from late 2011 into early 2013. They are also examining a control group of 2,500 people from the same age group and the same area who did not get sick. They want to compare their vaccination history against those who did contract whooping cough. “Since 2010 in the U.S., we have documented some genetic changes in the circulating strains of pertussis,” said Patsy Kelso, an epidemiologist from the Vermont Health Department. “We don’t know how much or whether the changes in pertussis are impacting vaccine effectiveness.” Whooping cough, also known as pertussis, is a highly contagious disease...