NEW YORK — A new strain of the bacterium that causes whooping cough immune to vaccines may have appeared in the United States, according to a brief published Thursday in the New England Journal of Medicine.
The brief, filed by officials from the Centers for Disease Control and Prevention and other health authorities, reported that a strain of Bordetella pertussis had been reported in Japan, France and Finland and may have appeared in Philadelphia, where 12 children were hospitalized between 2011 and 2012.
The new strain tests negative for pertactin, a protein involved in the bacteria's infection of humans and a component of acellular vaccines — vaccines that contain parts of cells as opposed to whole cells — used to prevent whooping cough. When researchers analyzed the Philadelphia samples, 11 of the 12 were found to test negative for pertactin.
The researchers suggested more testing of samples from around the country in order to help understand the new pertactin-negative variants of the bacteria.