Whooping cough vaccine antigen disappearing from bacteria in US
Vaccines for whooping cough contain three to five protective antigens, the presence of which are critical to the vaccine’s effectiveness. But one of the antigens, pertactin, which had been present in almost all isolates of Bordetella pertussis in the US as late as 2010, is now absent from more than half of them, according to a paper published ahead of print in Clinical and Vaccine Immunology.
"These findings tell us that there is an evolutionary advantage to lacking the protein that may have important vaccine implications,” says first author Lucia C. Pawloski, of the Centers for Disease Control and Prevention, Atlanta, GA.
Pertussis is resurgent in the United States. More than 48,000 cases were reported in 2012, up from less than 8,000 in 2000. Prevalence peaks cyclically, every three to four years, and the former number may reflect a peak, but the general trend has been strongly upward since before the millennium.
The rise in cases may be due to more sensitive and specific diagnostics, better awareness of the disease among both doctors and the general public, and waning immunity from the current acellular vaccine. Although some people do not get their children vaccinated, and such children are at least eight times more likely to get the disease than those who receive all five recommended doses they are not the driving force behind the large scale outbreaks or epidemics, says Pawloski.
Colonization of tracheal epithelial cells by Bordetella pertussis