Whooping cough (pertussis) is a classic childhood illness. It is transferred by bacteria and causes paroxysmal coughing fits in those affected. International studies have shown that strains of Bordetella pertussis bacteria mutate (form polymorphisms) and this can make them more virulent in some cases. These new strains are also to be found in Austria, as has been demonstrated by a study coordinated by MedUni Vienna.
It is primarily the ptxP3 polymorphism in the promoter region of the pertussis toxin gene that could make Bordetella pertussis more virulent than previous strains. It is not yet clear whether this mutation is due to natural causes or is a response to vaccinations. However, it has been identified throughout the world.
Cases of whooping cough on the increase
Over the past few decades whooping cough has been of marginal significance in Austria because of the once high vaccination coverage of around 90%. However, now, the number of cases is increasing worldwide, not only in children but also in adults. Whereas in 1995 there were only 91 reported cases in Austria, the number had risen to 425 in 2012 (rising trend). There are several possible reasons for this. “We still need to find out whether this is due to the modified strains of bacteria or to the increasing vaccination fatigue amongst Austrians,” explains co-author Michael Duchêne of the Institute for Specific Prophylaxis and Tropical Medicine at MedUni Vienna, “the important thing is that standard vaccinations still work, even against the modified bacterial strains.”
Current vaccines still work
Vaccination against pertussis is part of a sextuple combination vaccination (diphtheria, tetanus, pertussis, poliomyelitis, haemophilus infl. B, hepatitis B) that is given to infants in their first year of life. The vaccination plan issued by the Federal Ministry of Health also recommends a booster vaccination at primary-school age (combination vaccination against pertussis, diphtheria, tetanus and polio) and every ten years during adulthood.
The study was coordinated by MedUni Vienna and conducted in collaboration with the Elisabethinen Hospital in Linz, MedUni Graz and the University of Veterinary Medicine of Vienna.
“Genetic Variation of Bordetella pertussis in Austria”. Birgit Wagner, Helen Melzer, Georg Freymüller, Sabine Stumvoll, Pamela Rendi-Wagner, Maria Paulke-Korinek, Andreas Repa, Frits R. Mooi, Herwig Kollaritsch, Helmut Mittermayer†, Harald H. Kessler, Gerold Stanek, Ralf Steinborn, Michael Duchêne, Ursula Wiedermann; PONE-D-14-23597 – [EMID:56873cb671ce5207].