The Pan American Health Organization (PAHO) and the World Health Organization (WHO) have ruled out the presence of wild poliovirus and vaccine-derived poliovirus (VDPV) in tissue samples taken from one case of acute flaccid paralysis in Venezuela.
In a report that was released internally on June 15 and made public on July 24, the organizations defined VDPV as a Sabin virus with genetic mutations which enable it to produce the disease, although it poses no risk of spreading or causing further outbreaks.
“An epidemiological update from PAHO reported that a 34-month-old boy had an onset of symptoms of acute flaccid paralysis (AFP) on April 29, 2018. This child lives in a community with low vaccination coverage in the Orinoco Delta of Delta Amacuro State (Venezuela).
“The global reference laboratory confirmed the presence of a Sabin type 3 virus. Isolation of Sabin type 3 poliovirus is possible in children and communities immunized with oral bivalent polio vaccine, which contains attenuated (weakened) type 1 and type 3 Sabin strains,” the PAHO said.
The child is being further evaluated clinically to determine alternative causes of paralysis. The final determination of whether or not it is associated with the polio vaccine will be made after and assessment of clinical and virological data 60 days after the onset of paralysis.