VDV1

VDV1 is an abbreviation that is most commonly encountered in public health literature to denote a vaccine-derived poliovirus type 1. This term describes a lineage of poliovirus that originated from the attenuated Sabin strains used in the oral polio vaccine and has accumulated genetic changes through replication in human hosts. VDV1 is distinguished from the original vaccine strains and from wild poliovirus type 1 (WPV1) by its genetic evolution, which can restore properties such as transmissibility.

Origin and transmission

Under conditions of inadequate population immunity, individuals vaccinated with live attenuated OPV can shed the attenuated virus. If the virus circulates in a community for an extended period, it may mutate. When isolates show genetic changes relative to the Sabin vaccine strain in a key region of the genome, they are classified as VDV1. Surveillance also distinguishes whether such circulation is localized (isolates not sustained in populations) or circulating (cVDPV), the latter prompting more intensive public health responses.

Detection and classification

Laboratories sequence poliovirus isolates to assess divergence from the corresponding Sabin strain. A designation of VDV1 is given when type 1 poliovirus shows sufficient genetic difference from the vaccine strain, indicating derivation from OPV rather than a wild-type infection. Public health authorities monitor these isolates to determine whether transmission is occurring within communities and to guide outbreak containment measures.

Public health implications

VDV1 poses a risk in regions with gaps in routine immunization. Responding strategies include targeted immunization campaigns, strengthening surveillance, and, in some settings, shifts from oral polio vaccine to inactivated polio vaccine to prevent further emergence. Efforts aim to halt transmission and progress toward polio eradication.

Note

VDV1 can appear in different contexts in other fields, but this article focuses on its designation in poliovirus surveillance.