An Australian-led study says the likely cause of a rise in whooping cough is a new vaccine which provides less protection than the old one.
The problem could be solved by providing booster shots, the researchers suggest.
A team led by Manoj Gambhir of Monash University, Thomas Clark in the US and Professor Neil Ferguson of the UK, worked with 60 years of data from the US to determine the best explanation for the recent increase.
About 500 cases of the highly contagious disease are being reported each month in New South Wales, up from 140 a month last year. Whooping cough becomes an epidemic every few years.
In a study in the journal PLOS Computational Biology, the authors investigate several hypotheses for the surge in cases.
They found that the level of protection of the acellular vaccine is lower than that of the previously-used whole-cell vaccine.
Other explanations of the upsurge include a steady increase in the reporting of cases over time, whether through better diagnostic techniques or an increasing awareness.
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