Vaccine-derived Polioviruses: Managing the risks

What are vaccine-derived polioviruses and vaccine-associated paralytic poliomyelitis?

The oral poliovirus vaccine (OPV) contains a live, attenuated (weakened) vaccine-virus. When this vaccine is administered, the weakened vaccine-virus replicates in the intestine and enters into the bloodstream, triggering a protective immune response. However, during this replication process, some of the vaccine-virus may genetically mutate from the original attenuated strain and become neurovirulent (able to cause paralysis and circulate in communities). The neurovirulent virus is referred to as vaccine-derived poliovirus (VDPV). This is a very rare event. In the 10 years leading up to 2015 there were around 750 cases of paralysis caused by VDPVs reported worldwide.

Three categories of VDPV are recognised:

  • Circulating VDPVs (cVDPVs)
  • Immunodeficiency-associated VDPVs (iVDPVs)
  • Ambiguous VDPVs (aVDPVs)

Vaccine-associated paralytic poliomyelitis (VAPP) is a rare event associated with OPV, which is caused by a strain of poliovirus that has genetically changed in the intestine from the original attenuated vaccine strain contained in OPV – it occurs within approximately 1 in 2.7million doses of OPV and is a one-time case, with no risk of spread to others.

VDPV and VAPP Research:

This area of research focuses on understanding and managing the long-term risks of polio relating to VDPVs and VAPP in the post-eradication era, including through the eventual cessation of OPV use in routine immunization programmes as soon as possible after certification of wild poliovirus eradication.

In the first instance, this involves more clearly characterizing the risks of all three types of VDPVs and VAPP.

Related links

What is vaccine-derived polio?

Learn more about VDPVs here

Kew et al. (2014) ‘Vaccine-Derived Polioviruses’, J Infect Dis. 210

Fact Sheet – VDPVs and VAPP

The Bumpy Road to Polio Eradication

Update on Vaccine-Derived Polioviruses – Worldwide, January 2014 – March 2015

Sutter et al. (2014) ‘Vaccine-Associated Paralytic Poliomyelitis: A Review of the Epidemiology and Estimation of the Global Burden’ J Infect Dis. 210 (suppl 1)

cVDPVs – Evaluating cVDPV emergence

Environmental surveillance, whereby sewage is sampled for polioviruses in order to track the virus’ transmission through human populations, is being conducted in a number of countries. This area of research aims to further quantify the risk of circulating vaccine-derived poliovirus (cVDPV) emergence in countries that have recently switched from using OPV to IPV or from trivalent to bivalent OPV. Furthermore, these studies provide more evidence on the important role of environmental surveillance which enables us to address polio outbreaks quickly, and target campaigns accurately.

Related Links and Studies:

Muhammad et al. (2016) ‘Contribution of Environmental Surveillance Toward Interruption of Poliovirus Transmission in Nigeria, 2012-2015’ J Infect Dis. 213 (Suppl 3)

Global Poliovirus Surveillance Data (2014 and 2015)

Sutter et al. (2014) ‘Switch from oral to inactivated poliovirus vaccine in Yogyakarta Province, Indonesia: summary of coverage, immunity, and environmental surveillance’ J Infect Dis. 210

Japan Aerospace Exploration Agency (JAXA) presentation on the use of GIS technology in environmental surveillance for polio eradication

iVDPVs – Defining the risk of iVDPV

A series of studies are measuring the rate of long-term excretion of vaccine-derived poliovirus from immunodeficient people. The purpose of this research is to better define the risk of immunodeficiency-related vaccine-derived polioviruses (iVDPVs).

Studies:

Sutter et al. (2014) ‘Poliovirus Excretion Among Persons With Primary Immune Deficiency Disorders: Summary of a Seven-Country Study Series’, J. Infect Dis 210

Dowdle et al. (2014) ‘Progress in the development of poliovirus antiviral agents and their essential role in reducing risks that threaten eradication’ J Infect Dis. 210 (Suppl 1)

Sutter et al. (2012) ‘Prevalence of prolonged and chronic poliovirus excretion among persons with primary immune deficiency disorders in Sri Lanka’ Vaccine 30(52)

Luby et al. (2012) ‘The feasibility of identifying children with primary immunodeficiency disorders: preparation for the polio post-eradication era in Bangladesh’, Vaccine 33(36)