The Molecular Evolution of Type 2 Vaccine-Derived Polioviruses in Individuals with Primary Immunodeficiency Diseases

The oral poliovirus vaccine (OPV), which prevents person-to-person transmission of poliovirus by inducing robust intestinal immunity, has been a crucial tool for global polio eradication. However, polio outbreaks, mainly caused by type 2 circulating vaccine-derived poliovirus (cVDPV2), are increasing worldwide. Meanwhile, immunodeficiency-associated vaccine-derived poliovirus (iVDPV) is considered another risk factor during the final stage of global polio eradication. Patients with primary immunodeficiency diseases are associated with higher risks for long-term iVDPV infections. Although a limited number of chronic iVDPV excretors were reported, the recent identification of a chronic type 2 iVDPV (iVDPV2) excretor in the Philippines highlights the potential risk of inapparent iVDPV infection for expanding cVDPV outbreaks. Further research on the genetic characterizations and molecular evolution of iVDPV2, based on comprehensive iVDPV surveillance, will be critical for elucidating the remaining risk of iVDPV2 during the post-OPV era.

Automated summary

The use of oral poliovirus vaccine (OPV) has been crucial for preventing person-to-person transmission of poliovirus, but challenges such as cVDPV2 and iVDPV infections pose risks for global polio eradication efforts. The identification of chronic type 2 iVDPV (iVDPV2) excretors highlights the potential risk of inapparent iVDPV infection for expanding cVDPV outbreaks. Further research on genetic characterizations and molecular evolution of iVDPV2 will be critical for elucidating the remaining risk of iVDPV2 in the post-OPV era.