This article is more than 5 years old. Information may no longer be current.
New strains of B. pertussis may complicate vaccination efforts
Click Here to Manage Email Alerts
Vaccination programs against whooping cough may not be fully effective because the bacteria that cause the disease have evolved new strains.
A team of Australian researchers found for the first time that two of the most common strains of the Bordetella pertussis bacteria in Australia have undergone significant genetic changes since 1997.
Those mutations coincided with changes to the type of vaccine used in Australia and with apparent increases in the number of cases of Australians contracting the highly contagious respiratory disease.
Before 1997, a whole cell vaccine was used; it was phased out during two years, and since 1999, a new acellular vaccine has been used.
“A key issue is that the whole cell vaccine contained hundreds of antigens, which gave broad protection against many strains of pertussis,” Ruiting Lan, of the University of New South Wales School of Biotechnology and Biomolecular Sciences, said in a press release. “But the acellular vaccine contains only three to five antigens. Our findings suggest that the use of the acellular vaccine may be one factor contributing to these genetic changes.”
There has been growing concern among public health officials in recent years about the rising incidence of pertussis in Australia. Several significant outbreaks occurred last year in western Sydney.
The researchers performed multilocus variable-number tandem-repeat analysis (MLVA) of 316 isolates collected during 40 years from Australia and three other continents, and they identified 66 MLVA types (MTs), including six predominant MTs.
Their findings suggested that although vaccination remains effective against some strains circulating in Australia, it may no longer protect against two strains in particular — MT27 and MT70.
Kurniawan J. Emerg Infect Dis. 2010;doi:10.3201/eid1602.081707.