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A new superbug is on the horizon. New research has shown that the bacterium behind whooping cough has evolved to become tougher, stealthier, and even more dangerous, with researchers warning that a new vaccine needs to be developed in the coming decade.
The recent study discovered that some strains of Bordetella pertussis, the bacterium responsible for whooping cough, found during the 2008-2012 epidemic in Australia have evolved to become more sneaky and robust. Some of the strains have even evolved to evade vaccine-generated immunity.
Reporting their findings in the journal Vaccine, microbiologists from the University of New South Wales in Australia revealed that the evolving bacterial strains had undergone new changes to better survive in their host. One of the key changes was the bacteria producing fewer immunogenic proteins, which alert the immune system to the pathogen and spark an immune response. Some strains have also developed more nutrient-binding and transport proteins, which enhance the bacteria’s ability to “feed” off their host.
Most worrying of all, these changes gave the bacteria a better chance of surviving in the host even if that person had been fully vaccinated against the disease. This ability to overcome vaccines might explain the recent resurgence of the illness, such as the 140,000 cases seen in the 2008-2012 epidemic, despite Australia’s high vaccination rates.
"Put simply, the bacteria that cause whooping cough are becoming better at hiding and better at feeding – they're morphing into a superbug,” Dr Laurence Luu, first study author and microbiologist at the University of New South Wales, said in a statement.
"We found the whooping cough strains were evolving to improve their survival, regardless of whether a person was vaccinated or not, by producing more nutrient-binding and transport proteins, and fewer immunogenic proteins which are not targeted by the vaccine," Dr Luu added.
Whooping cough can often be mistaken for a typical common cold when it first appears. However, it goes on to develop into a persistent cough, characterized by severe bouts of coughing that can last for several weeks or months. The condition gets its name because people with the illness often (but not always) make a “whoop” sound as they draw in a breath between coughing. It’s also highly contagious, able to spread through droplets splattered in the air when an infected person coughs.
In light of this new research, Luu and the team argue that a new vaccine needs to be developed and rolled out within the next decade.
However, importantly, this does not mean that current vaccinations are redundant. The current vaccines still do a good job of preventing most strains of B. pertussis, but researchers need to stay vigilant and keep their eye on how the disease is changing.
“It is critical that people are vaccinated to prevent the spread of whooping cough – the current vaccine is still effective for protecting against the disease – but new vaccines need to be developed in the long-term,” said study author Professor Ruiting Lan of the University of New South Wales.
"We emphasize that Australia must maintain its high vaccination coverage to protect vulnerable newborns who are not protected by maternal immunity and cannot complete the three-dose primary vaccine course until they are six months old," added Dr Luu.
