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, 2) in Afghanistan, the number of reported 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 towards polio eradication in Afghanistan during January 2020-November 2021 and updates previous reports. (3,4,5) 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, 4 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 [greater than or equal to] 2 years. Although challenges remain, vigorous, sustained polio eradication efforts in Afghanistan could result in substantial progress during 2022-2023.
The estimated national routine vaccination coverage with the third dose of bivalent OPV (bOPV containing Sabin types 1 and 3) (OPV3) among children aged 12 months was 73% in 2018 and 2019; the estimated 1-dose coverage with injectable inactivated poliovirus vaccine (IPV) in 2019 was 66%. (6) Nationwide, during 2020-2021 to date, 27% of children aged 6-59 months with nonpolio acute flaccid paralysis (NPAFP) (paralysis with no evidence of poliovirus infection, a proxy indicator of OPV3 coverage) had received 3 OPV doses through routine immunization services based on caretaker recall. The proportion of children aged 6-59 months with NPAFP who never received OPV through routine or supplementary immunization activities (SIAs) (7) increased from 1% in 2019 to 4% in 2020, and to 6% in 2021, with the highest provisional percentages in 2021 in the southern provinces of Zabul (32%), Nimroz (13%), and Hilmand (21%), and the western province of Badghis (19%). However, this proportion remained at or near 0% in most of the eastern provinces during 2019-2021 and decreased from 10% and 4.9% in the southeast provinces of Paktya and Khost to 0% and 2.4%, respectively.
During January 2020-November 2021, 10 OPV SIAs were conducted; 8 were national immunization days (NIDs) and 2 were subnational immunization days (SNIDs) targeting children aged <5 years. In addition, 4 case-response campaigns with type 1-containing monovalent OPV (mOPV), bOPV, or trivalent OPV (tOPV containing Sabin types 1, 2, and 3) were implemented during July-November 2020. In January and February 2020, during IPV fixed-site campaigns, IPV was administered to 159 833 (93%) children targeted in the accessible districts in the eastern provinces of Kunar, Nangarhar, and Laghman, and...