Whooping Cough Vaccine May Not be as Effective as Imagined, New Study Says

A government study released a new study on Monday which suggest the whooping cough vaccine doesn't seem to be working as well as expected.

The new study was conducted on baboons who were vaccinated against whooping cough, also known as pertussis, were found to still carry the illness in their throats and were able to still spread the disease.

"It could explain the increase in pertussis that we're seeing in the U.S.," said one of the researchers, Tod Merkel of the Food and Drug Administration.

According to the Centers for Disease Control and Prevention, the United States alone experienced about 50,000 cases of pertussis last year, with 18 deaths. The increase could be due in part to more sensitive tools to diagnose pertussis that were widely introduced in 2010, or to pockets of children whose parents oppose vaccination. 

For the study, the researchers infected four groups of baboons , each group containing three or four babies, by anesthetizing the animals and dripping a pertussis-containing solution into their noses. One group had already received the standard three doses of the acellular vaccine; a second received the whole-cell vaccine. Members of the third group had previously had whooping cough. Those in the fourth group had not had the disease and received no vaccine before being exposed.

"The baboon model has provided an illuminating insight into the epidemic as we are coping with it today," said William Schaffner, a professor of preventive medicine at Vanderbilt University, who was not involved in the study, according to the New York Times.