Study: Polio cases linked to vaccine mutation

Screen shot 2014-11-15 at 2.49.43 PMCases of polio linked to a mutation from the anti-polio vaccine periodically crop up. Just-released research pinpoints that problem as the cause of at least one outbreak and possibly more than one.

This problem occurs periodically, even though the once global disease has been largely confined to a handful of countries, thanks to a vigorous vaccination program supported mostly by Rotary International, the World Health Organization and the Bill and Melissa Gates Foundation.

Vaccination and education are the only tools to eradicate polio. It is a disease that is preventable but incurable. More information on the battle is available by clicking here.

However, The New York Times today reported:

“Scientists of the University of Bonn, together with colleagues from Gabon, are reporting alarming findings: a mutated virus that was able to resist the vaccine protection to a considerable extent was found in victims of an outbreak in the Congo in 2010. The pathogen could also potentially have infected many people in Germany.  

“The polio epidemic in the Congo in 2010 was especially serious — 445 people were verifiably infected, mostly young adults. The disease was fatal for 209 of them. This high mortality rate is surprising. Also important was the fact that many of those affected had apparently been vaccinated. Surveys indicated that half of the patients remembered having received the prescribed three vaccination dosages. To date the vaccination has been considered a highly effective weapon for containing the polioviruses that cause the disease.

“We isolated polio-viruses from the deceased and examined the viruses more closely,” explains Dr. Jan Felix Drexler, who is in the meantime working in the Netherlands. He carried out the study during his employment at the Institute for Virology of the University Hospital of Bonn, Germany, under the supervision of Prof. Christian Drosten, together with his colleagues from Gabon, Dr. Gilda Grard and Dr. Eric Leroy.

“The pathogen carries a mutation that changes its form at a decisive point.”

The result: the antibodies induced by the vaccination can hardly block the mutated virus and render it harmless.

The researchers have examined the success with which the new pathogen evades the immune system. To this purpose, they tested, among others, blood samples from 34 medical students of the University of Bonn. All of them were vaccinated in childhood with the usual methods against polio. And very successfully, as an initial test showed: The antibodies in the blood of the test subjects had no problem combating “normal” polio viruses. The situation was different with the mutated virus; the immune reaction was much weaker here. “We estimate that one in five of our Bonn test subjects could have been infected by the new polio virus, perhaps even one in three,” says Prof. Drosten.

The polio epidemic in the Congo was stopped with a massive vaccination program and hygiene measures. Even the current vaccines thus appear to be good enough to be effective when they are promptly and consistently administered.

The new pathogen is nonetheless a warning: “We can’t afford to sit back and do nothing,” the scientists warn. “We need to further increase the vaccination rate and develop new, more potent vaccines. Only in this way do we have a chance of permanently vanquishing polio.”

Back in October of 2007, The New York Times reported:

“Nigeria is fighting an unusual outbreak of polio caused by mutating polio vaccine, world health authorities say, but the only remedy is to keep vaccinating children there.

“Officials of the World Health Organization fear that news of the outbreak will be a new setback for eradication efforts in northern Nigeria, where vaccinations were halted in 2003 for nearly a year because of rumors that the vaccine sterilized Muslim girls or contained the AIDS virus. During that lull, polio spread to many new countries, although most have snuffed out the small outbreaks that resulted.

Officials deny suggestions that they kept the outbreak, which began last year, a secret, and say that they did not realize until recently that as many as 70 of Nigeria’s last 1,300 polio cases stemmed from a mutant vaccine virus rather than “wild type” virus, which causes most polio.

“It was an oversight on our part,” said Dr. Bruce Aylward, director of the polio eradication campaign for the W.H.O.”


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