What is containment?

Containment includes biosafety and biosecurity requirements for laboratories, vaccine production sites, or any other facility that handles or stores eradicated polioviruses, to minimize the risk of these viruses being released into the community. Containment also concerns risk mitigation measures associated with field use of some live oral polio vaccines. Containment of eradicated polioviruses is a key objective of the Polio Eradication and Endgame Strategic Plan 2019-2023, and will be critical for maintaining global polio-free status.

Two of three strains of wild poliovirus have been declared globally eradicated. In September 2015, the Global Commission for the Certification of Eradication of Poliomyelitis declared wild poliovirus type 2  as eradicated, and in October 2019, wild poliovirus type 3 followed. Laboratories and facilities worldwide, however, still handle or store the viruses for activities such as vaccine production and research. Further, live type 2 or type 3-containing oral polio vaccines continue to be used across the world for outbreak response or routine immunization.

It is important that all poliovirus type 2, and all wild and vaccine-derived poliovirus (VDPV) type 3, is destroyed, or safely and securely contained so these viruses are not released from facilities that retain them. It is also important that inventories and appropriate destruction of unused vaccine containing live type 2 strains is conducted as per GPEI guidelines. Currently, measures only apply to live type 2 containing vaccines used for outbreak response.

The accidental or deliberate release of the virus from one of these facilities, or potential emergence of VDPV due to vaccine mismanagement in areas of low population immunity could result in the return of these strains.

Minimizing the number of government designated ‘poliovirus–essential’ facilities reduces the risk of release of the virus and allows for stronger national and international oversight of containment activities, strengthening the likelihood that global containment standards can be met and maintained. Additionally, ensuring high quality outbreak response campaigns to VDPV2 outbreaks reduces the need for deployment of live type 2 containing vaccines.

Watch our animated video on containment.

Containment activities

At the 71st World Health Assembly, Member States adopted a resolution which urges the intensification of efforts to accelerate progress towards poliovirus containment globally.

Activities are underway to ensure that all poliovirus type 2 materials are destroyed, or safely and securely contained. Countries have conducted national inventories of facilities that handle or store wild and vaccine-derived poliovirus type 2, and have destroyed unneeded virus. They have designated facilities that will retain the virus, where it is needed, and are preparing to undergo the certification of these poliovirus-essential facilities. Similar activities for facilities that handle or store OPV2 and Sabin2 materials are in progress.

For type 3 poliovirus, the current focus is on ensuring countries conduct inventories and destroy wild and VDPV type 3 materials and/or designate facilities for their retention if critical.

More on containment