The strain — which standard vaccines only weaken and do not prevent — has previously been reported in France, Finland and Japan, the Associated Press reports. The new strain is not more lethal, but because it’s not prevented by the vaccine, more people get sick and more die. The new cases were reported at St. Christopher’s Hospital for Children in Philadelphia.
Last year was the worst for whooping cough in the past six decades. In 2012, the number of cases was 41,880, according to the Centers for Disease Control and Prevention. That included 18 deaths. A combination of resistant strains and a 1990s version of the vaccine with a shorter effective duration may be causing the spike in cases.
The new strain was isolated in France. Even with extensive testing in that country, the new bug accounts for 14% of all cases there.