By NewsDesk  @bactiman63

The twenty-seventh meeting of the Emergency Committee under the International Health Regulations (2005) (IHR) on the international spread of poliovirus was convened by the WHO Director-General recently and one of the main topics was the spread of circulating vaccine-derived poliovirus.

Image/CDC

The committee was very concerned that cVDPV2 continues to spread rapidly.  The number of cases in 2020 is 1009 (year to date), 254% higher than the total for 2019.  As in all the years following 2016 when OPV2 was withdrawn, the number of cVDPV2 cases globally has been greater than the number of WPV1 cases.

In the most recent quarterly routine analysis (July to September 2020) there has been evidence of exportation of cVDPV2 from: Pakistan to Afghanistan, Sudan to Egypt, Afghanistan to Iran, Côte D’Ivoire to Mali, Benin to Nigeria, Afghanistan to Pakistan, Chad to Sudan, Chad into Cameroon and more.

Based on the following factors, the risk of international spread of cVDPV2 appears to be currently very high:

  • The increasingly large number of cases, environmental detections and documented exportations across borders to both new countries and already infected countries;
  • The ever widening gap in population intestinal mucosal immunity in young children since the withdrawal of OPV2 in 2016;
  • The same factors regarding the COVID-19 pandemic as mentioned above;
  • The population of inaccessible children in Afghanistan that appears to be driving intense transmission there.