SALT LAKE CITY — The bacteria that cause whooping cough may be becoming resistant to vaccines, according to a recent study.
The study, published earlier this month in the New England Journal of Medicine, found signs of resistance in 11 of 12 children hospitalized for whooping cough in Philadelphia in 2011 and 2012. Most of the hospitalized children were newborns, although one was 9 and one was 14.
Cases of vaccine-resistant whooping cough had been previously documented in France, Finland and Japan.
The bacteria-resistant cases were found to have been lacking a protein included in the vaccine that helps create immunity to the disease.
The prospect of a vaccine-resistant whooping cough is worrisome to public health officials after recent outbreaks. 2012 was the worst year for whooping cough since 1955, with nearly 42,000 cases reported. Utah saw its highest numbers since 1946, when vaccines were made available for the disease. The state had 1,366 cases reported in 2012.
Deaths from the disease did not rise, though, possibly due to increasingly fast diagnoses and treatments. There were 18 deaths reported throughout the nation in 2012, with one in Utah.
One reason for the increase in whooping cough cases in the U.S. may be the type of vaccine used: A vaccine developed in the 1990s and now used throughout the nation has been shown not to last as long as earlier vaccines.
The Centers for Disease Control are hesitant to comment on the vaccine-resistant strain or potential reasons for the rise in whooping cough cases, though, saying more information is needed before conclusions can be drawn.