Whooping Cough Bacteria Evolves, 'Outsmarts' Current Vaccine, Researchers Say

After a massive whooping cough outbreak in 2012, researchers examined the genetic makeup of the pertussis bacteria to determine the cause of the outbreak. In England and Wales, 9,711 laboratory confirmed cases of whooping cough led to 14 infant deaths.

"This was much greater than the previous recent 'peak' year in 2008, in which 902 cases were reported despite levels of vaccine coverage and diagnostic methods not changing during this period," the authors of the research published this month in the Journal Of Infectious Diseases explained, adding, "Similar outbreaks have been reported across the globe contributing to the consensus that pertussis is a resurgent disease might no longer [be] effectively controlled by current vaccination programmes."

The researchers conducted an analysis of whooping cough bacteria's genomes and found, disappointingly, that the "acellular vaccine antigen encoding genes are evolving at higher rates than other surface protein encoding genes," among other findings. The researchers said that it was happening even before countries like the United States and the U.K. switched from the whole cell whooping cough vaccine to the acellular whooping cough vaccine, but the evolution of whooping cough bacteria has progressed more rapidly since the new vaccine was introduced a decade ago.

The researchers further added that the old whole cell vaccine produced longer immunity to whooping cough bacteria than the current acellular whooping cough vaccine and that the current vaccine may be generating an expanded pool of carriers, particularly teenagers. Inquisitr reported on the phenomenon that was discovered earlier this year whereby the whooping cough vaccine may lessen symptoms in people who are vaccinated, but that it does little to prevent contagiousness and might even spread the disease. Other research highlighted in that report was scientists' concerns that the vaccine might have even increased the dangers of the pertussis toxin.

"Increased transmission of B. pertussis in populations using ACVs compared to those using WCVs is proposed to contribute to resurgence," the authors of the current article wrote. "Our results raise fresh concerns over the ability of current acellular pertussis vaccines to continue to control disease."

Meanwhile, many in the media persist in blaming the resurgence in whooping cough almost entirely on unvaccinated children, such as a journalist in Boston who reported that vaccines waivers were to blame for a whooping cough outbreak in the area, even though none of the first 15 children who came down with the disease were under-vaccinated against whooping cough.

The BBC summarized the recent findings.

"They found proteins being targeted by the vaccine were mutating at a faster rate than other surface proteins not included in the vaccine. Potentially it means the bacteria is changing quickly to get around immune system's defences put in place with immunisation."
The research was conducted by scientists who have stated they have no financial interests in the outcome of the whooping cough bacteria research, and was funded by Public Health England PhD Studentship and the Wellcome Trust.

[Photo via the CDC]