The Global Polio Eradication Initiative (GPEI) reported this week on a advance notification of circulating vaccine-derived poliovirus-1 (cVDPV1) in Papua New Guinea.
Following identification last month of an Acute Flaccid Paralysis (AFP) case from which VDPV type 1 had been isolated, genetic sequencing of two VDPV1s from two non-household contacts of the AFP case, has now confirmed that VDPV1 is circulating and will be officially classified as a ‘circulating’ VDPV type 1 (cVDPV1).
The National Department of Health (NDOH) is closely working with the GPEI partners in launching a comprehensive response.
In related news, advance notification of a new cVDPV2 case was received this week from Ituri province, in the north-east of DR Congo, close to the border with Uganda. Initial investigations are ongoing, but early reports are that the child had onset of paralysis on 5 May 2018, and has a recent travel history with Haut Katanga. Genetic sequencing indicates the case is linked to the Haut Lomami/Tanganika/Haut Katanga outbreak.
The GPEI says Vaccine-derived polioviruses (VDPVs) are rare strains of poliovirus that have genetically mutated from the strain contained in the oral polio vaccine.
The oral polio vaccine contains a live, attenuated (weakened) vaccine-virus. When a child is vaccinated, the weakened vaccine-virus replicates in the intestine and enters into the bloodstream, triggering a protective immune response in the child. Like wild poliovirus, the child excretes the vaccine-virus for a period of six to eight weeks. Importantly, as it is excreted, some of the vaccine-virus may no longer be the same as the original vaccine-virus as it has genetically altered during replication. This is called a vaccine-derived poliovirus.
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