Update on Immunodeficiency-Associated Vaccine-Derived Polioviruses - Worldwide, July 2018-December 2019

Area of Science:

• Virology
• Immunology
• Public Health

Background:

• The Global Polio Eradication Initiative has drastically reduced wild poliovirus (WPV) cases since 1988 through widespread oral poliovirus vaccine (OPV) use.
• OPV, despite its safety, can rarely lead to vaccine-derived polioviruses (VDPVs) with prolonged circulation, causing outbreaks in under-vaccinated areas.
• Immunodeficiency-associated VDPVs (iVDPVs) are found in individuals with primary immunodeficiency (PID) and pose risks of paralysis, death, and further VDPV spread.

Purpose of the Study:

• To update the status of iVDPV cases detected between July 2018 and December 2019.
• To highlight the importance of surveillance for poliovirus infections in patients with PID.
• To emphasize the need for expanded PID surveillance to mitigate iVDPV spread and support global polio eradication.

Main Methods:

• Review and reporting of iVDPV cases identified in patients with PID.
• Integration of PID surveillance with existing acute flaccid paralysis (AFP) surveillance systems.
• Monitoring of poliovirus excretion in individuals with PID.

Main Results:

• Sixteen new iVDPV cases were reported from five countries (Argentina, Egypt, Iran, Philippines, Tunisia) between July 2018 and December 2019.
• Surveillance among patients with PID has identified an increasing number of iVDPV excretors.
• iVDPV infection can lead to severe outcomes in PID patients and poses a risk for VDPV transmission.

Conclusions:

• Enhanced surveillance for poliovirus infections in patients with PID is crucial for early detection of iVDPV excretion.
• Identifying and monitoring iVDPV excretors can help prevent VDPV spread and potential outbreaks.
• Continued efforts in PID surveillance are vital for achieving and maintaining the eradication of all polioviruses.