About 142,000 Australian got whooping cough during a major epidemic which ended in 2012. Nine babies died during the five years.
Now researchers say they’ve detected a change in the bacterium which causes whooping cough, Bordetella pertussis, and they think is is the disease trying to get around the vaccine.
This could mean reduced effectiveness of the vaccine.
A team of researchers analysed strains of Bordetella pertussis from across Australia and found that many strains no longer produce a key surface protein called pertactin.
About 80 per cent of the 2012 whooping cough cases in Australia studied by the team were caused by pertactin-free strains.
“It’s like a game of hide and seek,” says the senior author of the study, Associate Professor Ruiting Lan, of the University of New South Wales School of Biotechnology and Biomolecular Sciences.
“It is harder for the antibodies made by the body’s immune system in response to vaccination to ‘search and destroy’ the whooping cough bacteria which lack pertactin.
“This could mean that these pertactin-free strains have gained a selective advantage over bacterial strains with the pertactin protein.”
Pertactin-free strains of pertussis have also been detected overseas, including France and the United States.
“The fact that they have arisen independently in different countries suggests this is in response to the vaccine,” says Associate Professor Lan.
The study is published in the journal Emerging Infectious Disease.
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