Following unconfirmed reports on 8 June of suspected polio re-emergence in Venezuela, final laboratory testing has confirmed the cause of the paralysis is not wild poliovirus or vaccine-derived poliovirus, according to a release from WHO.
A 34-month old child had presented with symptoms of acute flaccid paralysis (AFP) on 29 April, from a community with low vaccination coverage in Orinoco delta, Delta Amacuro state.
A Sabin type 3 poliovirus was isolated from stool samples of the child. Isolation of Sabin type 3 poliovirus can be expected in children and communities immunized with bivalent oral polio vaccine, which contains attenuated (weakened) type 1 and type 3 Sabin strains. Final laboratory analysis received on Friday has confirmed that the AFP symptoms are not associated with wild or vaccine-derived poliovirus.
A number of conditions or infections can lead to AFP, poliovirus being just one of them. As part of global polio surveillance efforts, every year more than 100 000 AFP cases are detected and investigated worldwide. Clinical evaluation of the child is underway to determine the cause of the paralysis. The most important point is that the child should be provided with appropriate care and support.
While wild and vaccine-derived polio have both been ruled out as the cause of this child’s symptoms, this area of Venezuela is experiencing vaccination coverage gaps. It is critical that countries maintain high immunity to polio in all communities, and strong disease surveillance, to minimize the risk and consequences of any eventual poliovirus re-introduction or re-emergence.
The partners of the Global Polio Eradication Initiative (GPEI) – WHO, the US Centers for Disease Control and Prevention, Rotary International, UNICEF and the Bill & Melinda Gates Foundation – will continue to support national and local public health authorities in these efforts, together with the Pan American Health Organization, which serves as the Americas Regional Office of WHO.