Vaccinated transmitted pertussis according to study

Vaccinated probably transmit whooping coughs

26/11/2013

Whooping cough may be transmitted by healthy and pertussis vaccinated people. In a smaller study by the US Food and Drug Administration (FDA), scientists have studied the transmission pathway for whooping cough. In the monkeys treated with the common vaccines, no whooping cough diseases were observed, but the vaccinated animals apparently transmit the pathogen to their conspecifics. In the opinion of the researchers, this may be the reason for the current high incidence of whooping cough in the US.

The US authorities registered about 42,000 whooping cough infections last year, even though the majority of the population is vaccinated. So many have not existed in the past 50 years, according to the FDA's study, published in the journal Proceedings of the US Academy of Sciences (PNAS). For Tod J. Merkel and his colleagues from the FDA, the development of an improved vaccine against whooping cough has therefore given priority.

Significance of the study
For the German experts of the Paul Ehrlich Institute (PEI) in Langen, Hesse, the testimony of this FDA study is due to the small number of experimental animals, "classified as low". Thus, the study could not show that the unvaccinated monkeys after the transmission of the pathogen by vaccinated monkeys really fell ill, said PEI President Klaus Cichutek. For him, the results are no reason to change the current vaccination recommendations in Germany.

According to the information provided by the Robert Koch Institute (RKI), this is due to „Bordetella pertussis“- Bacteria caused by whooping cough last year in the new federal states 5438 people. Compared to the same period of the previous year, the number has almost halved. Since March 2013, there has been a reporting obligation for this disease in the old federal states. Already in 1960 they had started in Germany with the vaccination against whooping cough. Initially, the so-called whole-germ vaccine frequently had severe side effects. The advantage of these vaccines compared to others is its longer efficacy, says Wiebke Hellenbrand of the RKI. It was not until the mid-1990s that acellular pertussis vaccines were used in Germany.

In their investigations, the US researchers had repeatedly treated small groups of monkeys a few months old with whole-germ or acellular vaccines. It turned out that only the unvaccinated animals fell ill. However, it took about three weeks before the pathogens could no longer be found.

The animals that had been given acellular vaccines, were free of bacteria until after six weeks and transferred in this time the pathogen on other animals. To the knowledge of the PEI there is currently no vaccine in development in the EU which would guarantee a longer and more comprehensive vaccine protection. „We are currently unable to control whooping cough, but we control the number of cases by further improving vaccination rates, especially among adolescents and adults“, says RKI expert Hellenbrand. People who have close contact with babies should vaccinate themselves. The vaccine must be renewed regularly, at the latest after ten years. (Fr)

Image: Thomas Siepmann