Genetic Characterization of Novel Oral Polio Vaccine Type 2 Viruses During Initial Use Phase Under Emergency Use Listing — Worldwide, March–October 2021 | MMWR - ISS-G20 Laboratorium Repository

What is already known about this topic?

Sabin oral polio vaccine virus can revert to neurovirulence in populations with low immunity. A genetically stable novel type 2 oral poliovirus vaccine (nOPV2) was authorized for outbreak response use under a World Health Organization Emergency Use Listing.

What is added by this report?

Global nOPV2 genomic surveillance during March–October 2021 confirmed genetic stability of the primary attenuating site.

What are the implications for public health practice?

nOPV2 is used to respond to poliovirus outbreaks with comparatively low risk for generating new circulating strains. Given the background immunity, population dynamics, and scale of use, the consistent pattern of genetic characteristics of nOPV2 isolates is encouraging. nOPV2 surveillance should continue for the duration of the Emergency Use Listing.

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