The changing face of Bordetella pertussis
An epidemic in the 1950s saw 11,000 infections per 100,000 infants, but by 2010 the infection rate had dropped to 110 per 100,000 infants aged up to 12 months, and just seven in 100,000 for the whole population.
“The B. pertussis population in Denmark has changed from having a higher genetic diversity… towards the dominance of single types,” the authors said, also noting intercontinental travel had surged in the post-vaccine era.
“Identified strains currently circulating in Denmark resemble the types observed in other European countries.”
Emerg Infect Dis 2012, in press