Concerning trends in spread of vaccine derived polioviruses

2 Sep, 2018
, Source:
Below are extracts from the eighteenth meeting of the Emergency Committee under the International Health Regulations (2005) (IHR) convened on 15 August 2018 by the Director General  at WHO headquarters with members, advisers and invited Member States :
Vaccine derived poliovirus
The committee was very concerned by the increase in circulating vaccine derived polioviruses (cVDPV).  Since the last meeting, new emergences with circulation of VDPV have been detected in Papua New Guinea, DR Congo (Mongala) and Nigeria (Sokoto).  In Nigeria and DR Congo multiple lineages of cVDPV2 are circulating concurrently, and in Somalia, both cVDPV2 and cVDPV3 are circulating. 
Control of the outbreaks in DR Congo remains difficult to achieve.  Gene sequencing and analysis has shown that there have been three different cVDPV2 sub-types circulating.  The analysis of the newly detected cVDPV2 in Mongala Province indicates the virus has emerged after OPV2 withdrawal in 2016.  Conflict and population movement within and outside DR Congo represent a risk of further spread.  The detection of cVDPV2 in Ituri Province far from previously detected cases and adjacent to the border with Uganda heightened these concerns and is an example that the virus can spread long distances.  The outbreaks of Ebola virus disease further complicates the response.
The new outbreak of cVDPV1 in PNG highlights that there are vulnerable areas of the world not usually the focus of eradication efforts.  The swift action of the Government of PNG in declaring a national public health emergency was welcomed, and highlights the utility of the Temporary Recommendations in such circumstances.
The outbreaks of cVDPV2 in Somalia and Kenya, and cVDPV3 in Somalia are of major concern, particularly the apparent international spread between Somalia and Kenya. 
The outbreaks of cVDPV2 in Jigawa, and for the second time in Sokoto, Nigeria, again underlines the vulnerability of northern Nigeria to poliovirus transmission.  Routine immunization coverage remains very poor in many areas of the country, although the national emergency programme to strengthen routine immunisation is beginning to make an impact in some areas….
The Committee unanimously agreed that the risk of international spread of poliovirus remains a Public Health Emergency of International Concern (PHEIC), and recommended the extension of Temporary Recommendations for a further three months
Additional considerations
The outbreak in Papua New Guinea again highlights the ongoing vulnerability of some parts of the world to polioviruses. The committee urged countries in close proximity to the current outbreaks, such as Ethiopia, South Sudan and Indonesia to strengthen polio surveillance and routine immunization.
The Committee noted that the extension of the PHEIC for over four years in the context of the end game of the global eradication effort, was an exceptional use of the IHR.  The committee noted that some stakeholders are questioning whether this continued declaration of a PHEIC may weaken its impact as a tool to address global health emergencies, and specifically whether it continues to have utility noting that the risk of international spread appears to have substantially diminished since 2014.  It noted that it was not originally envisaged that a PHEIC would continue for such a long interval, but the committee feels that the circumstances of an eradication program such as polio are unique.  The committee was deeply concerned that the abrupt removal of the PHEIC might send out the wrong message to the global community and might reverse the gains made in reducing the risk of international spread in some areas.  There is sound evidence that the Temporary Recommendations have been an important factor in reducing the risk of international spread since 2014 [1][2].  The committee requested the secretariat to review whether there were alternative approaches or tools to achieve the same outcomes as the Temporary Recommendations for the polio PHEIC and report back to the committee in three months. 
Based on the current situation regarding WPV1 and cVDPV, and the reports provided by Afghanistan, DR Congo, Nigeria, Pakistan, Papua New Guinea and Somalia, the Director-General accepted the Committee’s assessment and on 27 August 2018 determined that the situation relating to poliovirus continues to constitute a PHEIC, with respect to WPV1 and cVDPV.  The Director-General endorsed the Committee’s recommendations for countries meeting the definition for ‘States infected with WPV1, cVDPV1 or cVDPV3 with potential risk for international spread’, ‘States infected with cVDPV2 with potential risk for international spread’ and for ‘States no longer infected by WPV1 or cVDPV, but which remain vulnerable to re-infection by WPV or cVDPV’ and extended the Temporary Recommendations under the IHR to reduce the risk of the international spread of poliovirus, effective 27 August 2018.
This entry was posted on Sunday, September 2nd, 2018 at 9:13 am and is filed under Blog.

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