The twenty-sixth meeting of the Emergency Committee under the International Health Regulations (2005) (IHR) on the international spread of poliovirus was convened and opened by the WHO Deputy Director-General on 14 October 2020 with committee members attending via video conference, supported by the WHO Secretariat. Dr Zsuzsana Jakab in opening remarks on behalf of Dr Tedros congratulated all those involved in eliminating wild polioviruses from the WHO African Region despite some very challenging obstacles.
The COVID-19 pandemic and the ongoing spread of cVDPV2 (Circulating vaccine-derived poliovirus type 2) were both growing major challenges, which would require strenuous efforts to overcome in order to restart progress toward global polio eradication.
The Emergency Committee reviewed the data on wild poliovirus (WPV1) and circulating vaccine derived polioviruses (cVDPV). The following IHR States Parties provided an update at the video conference or in writing on the current situation in their respective countries: Afghanistan, Chad, Egypt, Guinea, Pakistan, Somalia, South Sudan, Sudan and Yemen.
Wild poliovirus
The higher incidence of global WPV1 cases seen during 2020 continues, with 121 cases reported between 1 January – 5 October 2020 compared to 85 for the same period in 2019, a 42% increase. Last year there were 176 WPV1 cases, the highest number reported since the PHEIC was declared in 2014, when there were 359 cases in nine countries. The lowest number of WPV1 cases was reported in 2017, when only 22 cases were found. No wild polio cases have been detected outside of Pakistan and Afghanistan since the last cases in Nigeria in 2016 four years ago. The number of positive environmental samples has increased 70% to 375 compared to 221 for the same time last year. Since the last meeting, exportation of WPV1 from Pakistan to Afghanistan has been documented.
The Committee noted that based on results from sequencing of WPV1 since the last committee meeting in June, there were further instances of international spread of viruses from Pakistan to Afghanistan. The ongoing frequency of WPV1 international spread between the two countries and the increased vulnerability in other countries where routine immunization and polio prevention activities have both been adversely affected by the COVID-19 pandemic are two major factors that suggest the risk of international spread may be at the highest level since 2014. While border closures and lockdowns may mitigate the risk in the short term while in force, this would be outweighed in the longer term by falling population immunity through disruption of vaccination and the resumption of normal population movements.
On the other hand the certification of the WHO African Region as wild polio free in August 2020 indicated a lessening of the global risk from this previous source.
Vaccine derived poliovirus (VDPV)
The committee was very concerned that the international spread of cVDPV2 continues, causing new outbreaks in Guinea, South Sudan and Sudan, the latter two due to importation of a cVDPV2 lineage that emerged in Chad in 2019. The same virus has also been detected in sewage in Cairo, Egypt but with no evidence of local circulation. The number of cases in 2020 is 409 as at 5 October 2020, already exceeding the 378 cases reported for the whole of 2019. As in all other years after 2016 when OPV2 was withdrawn, the number of cVDPV2 cases has been greater than the number of WPV1 cases in 2020. However, the number of sub-types / lineages detected so far in 2020 is 27, compared to 42 for the whole of 2019, and the number of newly emerged viruses is only seven so far this year, compared to 38 during 2019.
Cross border spread of cVDPV2 is now occurring regularly. Based on analysis by the US CDC of isolates, in the three months from April to June 2020, there has been evidence of exportation of cVDPV2 from:
· Pakistan to Afghanistan
· Côte d’Ivoire to Mali
· Guinea to Mali
· Côte d’Ivoire to Ghana, and Ghana to Côte d’Ivoire
· CAR to Cameroon
· Chad to Sudan and South Sudan
· Ghana to Burkina Faso
COVID-19
The committee heard that nearly all countries (90%) have experienced disruption to health services especially in low- and middle-income countries, according to a survey of 105 countries conducted March – June 2020. Routine immunization particularly outreach services was the area most frequently reported as disrupted.
The committee was very concerned that most of the current outbreak countries have had to delay immunization responses in recent months, meaning that transmission is likely continuing unchecked. Furthermore, there appear to be significant falls in surveillance indicators in many of the outbreak countries, such as drops in AFP reporting rates, and lesser drops in environmental sampling. Vaccine management and supply has been significantly impacted. More than 60 campaigns in 28 countries have been postponed since late February and early March. Vaccine supplies have been disrupted in many ways, with some quantities already in-country at risk of exceeding their expiry data and therefore unusable. Some suppliers are reaching storage capacity and may well be forced to stop production.
Although the resumption of Supplementary Immunization Activities (SIAs) is now occurring, the waves of the pandemic are expected to fluctuate considerably from country to country and across the WHO Regions, so the program will need to adjust according to the COVID-19 situation for the foreseeable future.
Although in general surveillance processes are continuing, there are clear signs of a significant drop in AFP case reporting, including in endemic countries, some outbreak countries and some other non-infected high-risk countries.
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https://www.who.int/news/item/22-10-2020-statement-of-the-twenty-sixth-p...
