Australasian Science: Australia's authority on science since 1938

Whooping Cough Upsurge Is Due to Weaker Vaccine

Analysis of 60 years of data on pertussis (whooping cough) has concluded that recent increases in the disease are likely to be due to the use of a new acellular vaccine that provides less protection than the older whole-cell vaccine.

In 2012 the USA reported the highest number of pertussis cases since 1955. Other explanations of the upsurge in pertussis – most notably a steady increase in the reporting of cases over time, whether through better diagnostic techniques or an increasing awareness of the disease among medical practitioners – do not appear to be as fundamental as a change in protection between the current and former vaccines.

“We used a rigorous procedure for fitting several mathematical models to the data, and we found that a drop in protection was always necessary to reproduce the rising pattern of disease we’ve seen in the US,” says Dr Manoj Gambhir of Monash University. “Crucially, our model also matches the age pattern of disease.”

However, the study’s findings, published in PLOS Computational Biology, also suggest that the efficacy of the current acellular vaccine is not much lower than the older whole-cell vaccine, and therefore booster doses may be sufficient to curtail epidemics while novel vaccine research continues.

“Pertussis has also been on the rise in several countries around the world, and we are eager to look at data from other countries to see whether the explanation for this is similar to what we found for the US,” says co-author Dr Thomas Clark of the Centers for Disease Control and Prevention.