Thanks to effective vaccination, polio is considered nearly eradicated. Each year, only a few hundred people are stricken worldwide.
However, 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.
Results of research conducted by scientists at the University of Bonn have been published in the magazine PNAS.
The polio epidemic in the Congo in 2010 was especially serious: 445 people were verifiably infected, mostly young adults, and the disease was fatal for 209 of them. What is important was the fact that many of those affected had apparently been vaccinated.
“We isolated polio-viruses from the deceased and examined the viruses more closely,” explains Dr Jan Felix Drexler, who carried out the study during his employment at the Institute for Virology of the University Hospital of Bonn under the supervision of Prof Christian Drosten, together with 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 of the research indicated that the antibodies induced by the vaccination hardly block the mutated virus and render it harmless.
The World Health Organization (WHO) has undertaken the goal of eradicating the polio virus in coming years. Because the polio virus can also only be transmitted from person to person, there are thus no pathogen reservoirs in animals from which the disease could spread repeatedly.
In addition, the polio vaccines also offer extraordinary protection – however, this doesn’t apply when the virus mutates.
“When such an altered pathogen encounters a population that has not been consistently vaccinated enough, then things get dangerous,” the scientists warn.
“We can’t afford to sit back and do nothing,” they add. “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.”