Why is Polio resurfacing now?
After the detection of the poliomyelitis virus in London, it is the turn of the United States to face an identical situation.
Following the confirmation of a case of paralytic poliomyelitis in Rockland County, New York, USA in June, federal health officials have stepped up surveillance for poliovirus throughout the state’s sewage. A few days ago they announced that virions were identified in June and July in two different geographical areas: in Orange County and again in Rockland County.
The confirmed case involves a young adult, whose identity is unknown, who presented with a paralyzed leg at a Rockland County hospital. Doctors quickly confirmed the presence of the polio virus in this unvaccinated patient. The person would have been infected due to two factors: his failure to vaccinate against poliomyelitis and his exposure to a strain of poliovirus. Phylogenetic analysis of the strain isolated from this patient indicates that it is similar to those used in the oral poliomyelitis (OPV) vaccine. A person who has been given OPV sheds virions in the stool, which can remain circulating in communities where polio vaccination is inadequate.
In circulation, the virus accumulates mutations that can make it pathogenic and neurotoxic again – it attacks the spinal cord. If an unvaccinated person comes into contact with such a strain, it can trigger the symptoms of polio. However, Health authorities state that this case is not due to vaccination.
OPV is no longer administered in the United States or Europe but is still used in other countries around the world where it effectively protects children from this incurable virus and deadly diseases at low cost. In the West, children are now vaccinated with Inactivated polyvaccine.