U.S. Poliovirus Containment Survey Definitions

Vaccines and innactivation

Inactivated Poliovirus Vaccine (IPV)

The inactivated poliovirus vaccine was developed in 1955 by Salk and Youngner. IPV is a killed-virus vaccine and is administered by injection.

Inactivation

Procedures that render PV non-infectious and unable to grow or replicate. Inactivation occurs in the absence of transfection reagents (e.g., transfection) or cellular manipulation (e.g., electroporation).

Procedures to inactivate PV may include, but are not limited to:

• Nucleic acid or protein extractions
• Specimen fixations (e.g., formalin, acetone)
• Irradiation
• Heat
• Enzymes (e.g., lysozymes)

Oral Poliovirus Vaccine (OPV)

Attenuated poliovirus strains (approved for use in oral polio vaccines by national regulatory authorities, principally Sabin strains). Also called 'Sabin vaccine', OPV contains live, attenuated (weakened) poliovirus strains.

OPV formulations include:

• Trivalent OPV (tOPV)
  • Contains all three serotypes of Sabin strains (1 + 2 + 3)
  • Use of tOPV ended in April 2016
• Bivalent OPV (bOPV)
  • Contains Sabin strains 1 + 3
  • As of April 2016, only bOPV is used routinely
• Monovalent OPV (mOPV)
  • Contains only one serotype of Sabin strain

Vaccine derived poliovirus (VDPV)

Classified with wild polioviruses and usually demonstrate 1–15% sequence differences from the parental OPV strain. They may have circulated in the community (cVDPV). They may also have replicated for prolonged periods in immunodeficient subjects (iVDPV). VDPV can also be ambiguous and of unknown origin (aVDPV).

Infectious materials

Infectious Materials (IM): OPV/Sabin

Infectious materials includes:

• Cell culture isolates and reference OPV/Sabin strains
• Seed stocks and live virus materials from OPV production
• Environmental sewage or water samples that have tested positive for the presence of OPV/Sabin strains
• Fecal or respiratory secretion samples from recent OPV recipients
• Infected animals or samples from such animals, including poliovirus receptor transgenic mice
• Derivatives produced in the laboratory that have capsid sequences from OPV/Sabin strains
• Cells persistently infected with poliovirus strains whose capsid sequences are derived from OPV/Sabin strains

Infectious Materials (IM): Wild Poliovirus/Vaccine-derived Poliovirus (WPV/VDPV)

Infectious materials includes:

• Clinical materials from confirmed wild poliovirus (including VDPV) infections.
• Environmental sewage or water samples that have tested positive for the presence of wild polioviruses.
• Cell culture isolates and reference strains of wild poliovirus.
• Seed stocks and infectious materials from IPV production.
• Infected animals or samples from such animals, including human poliovirus receptor transgenic mice.
• Cells persistently infected with poliovirus strains whose capsid sequences are derived from wild poliovirus.
• Derivatives produced in the laboratory that have capsid sequences from wild polioviruses, unless demonstrably proven to be safer than Sabin strains.*

*The safety of new derivatives containing wild poliovirus capsid sequences will be assessed by an expert panel, on the basis of comparison to reference Sabin strains for (i) degree and stability of attenuation; (ii) potential for person-to-person transmission; and (iii) neurovirulence in animal models.

Potentially infectious materials

Potentially infectious materials includes:

• Fecal or respiratory secretion samples and their derivatives (e.g., stool suspensions, extracted nucleic acids, etc.) collected for any purpose in a geographic area where WPV/cVDPV is present or OPV is being used at the time of collection.
• Products of such materials (above) from PV-permissive cells or experimentally infected polio-susceptible animals.
• Uncharacterized enterovirus-like cell culture isolates from human specimens from countries known or suspected to have circulating WPV/VDPV or use of OPV at the time of collection.
• Respiratory and enteric virus stocks derived from PV PIM and handled under conditions conducive to maintaining the viability or enabling the replication of incidental PV.
• Environmental samples (i.e., concentrated sewage, wastewater) collected from areas known or suspected to have circulating WPV/VDPV or use of OPV at the time of collection.

General terms

Circulating VDPV (cVDPV)

VDPV isolates for which there is evidence of person-to-person transmission in the community.

Global Action Plan IIII (GAPIV)

The WHO global action plan to minimize poliovirus facility-associated risk after type-specific eradication of wild polioviruses and sequential cessation of OPV use (GAPIV). The 4th edition of the Global Action Plan (GAPIV) aligns the safe handling and containment of poliovirus infectious and potentially infectious materials with the WHO Endgame Strategy and replaces the 2014 3rd edition of the WHO global action plan for laboratory containment of wild polioviruses.

Nucleic Acid, Poliovirus

Nucleic Acid, Poliovirus refers to full-length poliovirus RNA, cDNA, and total nucleic acid extracted from poliovirus infectious materials (e.g., a virus isolate) or potentially infectious materials (e.g., stool, respiratory specimen, sewage) using methods demonstrated to inactivate poliovirus, or synthesized full-length RNA/cDNA (e.g., cDNA clone, synthetic transcript).

Poliovirus nucleic acid can be handled outside poliovirus containment under the condition that these materials will not be introduced into polio-permissive cells or animals (as defined in GAPIV and the "Guidance for non-poliovirus facilities to minimize risk of sample collections potentially infectious for polioviruses") with or without transfection reagent. The use of poliovirus nucleic acids with polio-permissive cells that have been rendered and validated as non-polio permissive by techniques such as genetic engineering, etc. are not subject to these requirements.

Poliovirus

A picornavirus consisting of three serotypes: 1, 2 and 3; protective immunity is type-specific. Poliovirus serotypes are further subdivided into wild (circulating in nature) and Sabin strains (attenuated strains used for oral polio vaccines). Poliovirus types 2 and 3 have been eliminated in the wild. In this current stage of polio eradication, only type 1 wild poliovirus continues to circulate in endemic areas. It is highly infectious and causes paralytic polio.

Sample

1. Any material–biological, clinical or environmental sample – taken as a representation of a whole, used for analysis or medical diagnosis.
2. An unknown for which an assay is testing for an outcome.

Specimen

See definition for 'Sample.'

WHO Regions:

WHO Member States are grouped into six WHO regions:

• Africa
• Americas
• South-East Asia
• Europe
• Eastern Mediterranean
• Western Pacific