Progress Toward Poliomyelitis Eradication - Afghanistan, January 2020-November 2021

Abstract

Wild poliovirus types 2 and 3 were declared eradicated in 2015 and 2019, respectively, and, since 2017, transmission of wild poliovirus type 1 (WPV1) has been detected only in Afghanistan and Pakistan. In 2020, these countries reported their highest number of WPV1 cases since 2014 and experienced outbreaks of type 2 circulating vaccine-derived poliovirus (cVDPV2)* (1); in Afghanistan, the number of WPV1 cases reported increased 93%, from 29 in 2019 to 56 in 2020, with 308 cVDPV2 cases reported. This report describes the activities and progress toward polio eradication in Afghanistan during January 2020-November 2021 and updates previous reports (2-4). Despite restrictions imposed by antigovernment elements since 2018, disruption of polio eradication efforts by the COVID-19 pandemic, and civil and political instability, eradication activities have resumed. During January-November 2021, four WPV1 cases and 43 cVDPV2 cases were detected, representing decreases of 93% from 56 and 85% from 281, respectively, during the same period in 2020. After the assumption of nationwide control by the current de facto government of Afghanistan during August 2021, health officials committed to oral poliovirus vaccine (OPV) campaigns nationwide, with the potential to vaccinate approximately 2.5 million children against poliovirus who were previously not accessible for ≥2 years. Although challenges remain, vigorous, sustained polio eradication efforts in Afghanistan could result in substantial progress toward eradication during 2022-2023.

Figure 1

Cases of wild poliovirus type 1 and circulating vaccine-derived poliovirus type 2,^,† by province and period — Afghanistan, January 2020–November 2021 Abbreviations: cVDPV2 = circulating vaccine-derived poliovirus type 2; WPV1 = wild poliovirus type 1. * cVDPVs are genetically linked VDPV2 isolates for which there is evidence of person-to-person transmission in the community. ^† Total cases by period: January–June 2020 = 34 WPV1 and 54 cVDPV2; July–December 2020 = 22 WPV1 and 254 cVDPV2; and January–November 2021 = 4 WPV1 and 43 cVDPV2. ^§ Data as of January 11, 2022.

Figure 2

Number of wild poliovirus type 1 cases (n = 60) and circulating vaccine-derived poliovirus type 2 cases, by month of onset of paralysis (n = 351) — Afghanistan, January 2020–November 2021 Abbreviations: cVDPV2 = circulating vaccine-derived poliovirus type 2; WPV1 = wild poliovirus type 1. * cVDPVs are genetically linked VDPV2 isolates for which there is evidence of person-to-person transmission in the community. ^† Data as of January 11, 2022.