Wednesday, March 02, 2016

WHO: Statement Of 8th IHR Committee On Polio As A PHEIC

Credit WHO


While Zika is getting all of the media's attention these days, not quite two years ago (May 2014) - after convening a meeting of their Emergency Committee - we saw the WHO Declare  Polio Spread A Public Health Emergency Of International Concern (PHEIC).

Since then the IHR committee has met regularly to discuss progress in eradicating Polio and consider its status. Yesterday the WHO posted the results of their 8th consultation, where they decided to extend the PHEIC designation another 3 months. 

While noting that progress has been made over the past two years in controlling wild type polio, they cited two  recent reports of exportations last fall from Pakistan into Afghanistan. 

And while relatively rare, we continue to see scattered reports of vaccine derived Poliovirus (cVDPV) around the world.  The IHR committee reports: 

In 2015, six outbreaks of circulating vaccine derived poliovirus have occurred – three cVDPV type 1 outbreaks (Ukraine, Madagascar and Lao People’s Democratic Republic) and three cVDPV type 2 outbreaks (Myanmar, Nigeria and Guinea). Six additional cases of cVDPV type 2 have been reported in Guinea since the last meeting.
These vaccine derived infections come from the use of the oral (Sabin) polio vaccine (OPV) which contains three attenuated (weakened) polio virus strains, that activates an immune response in the body, and for a few weeks causes the weakened virus to be shed in the feces. 

This is considered a `good’ side effect, for in areas with poor sanitation, this vaccine-virus can spread in the community for a limited time conveying extra immunity.

But as the WHO explains: 

On rare occasions, if a population is seriously under-immunized, an excreted vaccine-virus can continue to circulate for an extended period of time. The longer it is allowed to survive, the more genetic changes it undergoes. In very rare instances, the vaccine-virus can genetically change into a form that can paralyse – this is what is known as a circulating vaccine-derived poliovirus (cVDPV).

For Polio to be completely eradicated, the use of the OPV must eventually be  phased out, and the final push completed using the older inactivated Salk vaccine (see   Polio Eradication and Endgame Strategic Plan 2013–2018 ). 

Unlike the oral vaccine which has been the workhorse of the global polio eradication initiative, the inactivated polio vaccine (IPV) must be delivered via an injection, and by a trained health care professional.

IPV is also much more expensive than OPV, but is the only path to eradication. Follow the link below to read the entire IHR statement, I've only included some highlights from the text.

WHO statement
1 March 2016 

The eighth meeting of the Emergency Committee under the International Health Regulations (2005) (IHR) regarding the international spread of poliovirus was convened via teleconference by the Director-General on 12 February 2016. As with the seventh meeting, the Emergency Committee reviewed the data on circulating wild poliovirus as well as circulating vaccine-derived polioviruses (cVDPV). The latter is particularly important as cVDPVs reflect serious gaps in immunity to poliovirus due to weaknesses in routine immunization coverage in otherwise polio-free countries. In addition, it is essential to stop type 2 cVDPVs in advance of the globally synchronized withdrawal of type 2 OPV in April 2016. 

The following IHR States Parties submitted an update on the implementation of the Temporary Recommendations since the Committee last met on 10 November 2015: Afghanistan, Pakistan and Guinea.



The Committee unanimously agreed that the international spread of polio remains a Public Health Emergency of International Concern (PHEIC) and recommended the extension of the Temporary Recommendations for a further three months. The Committee considered the factors expressed in reaching this conclusion at the seventh meeting still applied:
  • The continued international spread of wild poliovirus during 2015 involving Pakistan and Afghanistan.
  • The risk and consequent costs of failure to eradicate globally one of the world’s most serious vaccine preventable diseases.
  • The continued necessity of a coordinated international response to improve immunization and surveillance for wild poliovirus, stop its international spread and reduce the risk of new spread.
  • The serious consequences of further international spread for the increasing number of countries in which immunization systems have been weakened or disrupted by conflict and complex emergencies. Populations in these fragile states are vulnerable to outbreaks of polio. Outbreaks in fragile states are exceedingly difficult to control and threaten the completion of global polio eradication during its end stage.
  • The importance of a regional approach and strong cross-border cooperation, as much international spread of polio occurs over land borders, while recognizing that the risk of distant international spread remains from zones with active poliovirus transmission.
  • Additionally with respect to cVDPV:
    • cVDPVs also pose a risk for international spread, and if there is no urgent response with appropriate measures, particularly threaten vulnerable populations as noted above;
    • The emergence and circulation of VDPVs in four WHO regions demonstrates significant gaps in population immunity at a critical time in the polio endgame;
    • There is a particular urgency of stopping type 2 cVDPVs in advance of the globally synchronized withdrawal of type 2 component of the oral poliovirus vaccine in April 2016.
 (Continue . . . )

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