Mutated polio virus resists vaccine protection

A new study has revealed that mutated polio virus which resists the vaccine's protection could pose a serious threat.

Scientists of the University of Bonn, together with colleagues from Gabon have reported that the polio epidemic in the Congo in 2010 caused by the mutated polio virus was especially serious. 445 people were verifiably infected, mostly young adults. The disease was fatal for 209 of them. This high mortality rate was surprising. The pathogen could also potentially have infected many people in Germany.

Also important was the fact that many of those affected had apparently been vaccinated. To date the vaccination has been considered a highly effective weapon for containing the polioviruses that cause the disease.

Dr. Jan Felix Drexler said that they isolated polio-viruses from the deceased and examined the viruses more closely and found that pathogen carried a mutation that changes its form at a decisive point, resulting in the antibodies induced by the vaccination could now hardly block the mutated virus and render it harmless.

The polio epidemic in the Congo was stopped with a massive vaccination program and hygiene measures. Even the current vaccines thus appeared to be good enough to be effective when they are promptly and consistently administered. The new pathogen was nonetheless a warning but the scientists suggested that further increases in the vaccination rate are required with the development of new, more potent vaccines.

The study is published in the magazine PNAS.