Thirteen WPV1 cases were confirmed in Afghanistan in 2016, a decrease of seven from the 20 cases reported in 2015. From January to June 2017, five WPV1 cases were reported, compared with six during the same period in 2016. The number of affected districts declined from 23 (including WPV1–positive acute flaccid paralysis [AFP] cases and positive environmental sewage samples) in 2015 to six in 2016. To achieve WPV1 eradication, it is important that Afghanistan’s polio program continue to collaborate with that of neighboring Pakistan to track and vaccinate groups of high–risk mobile populations and strengthen efforts to reach children in security–compromised areas.

Estimated routine immunization coverage of infants with 3 doses of oral poliovirus vaccine (OPV3) in Afghanistan was 60% in both 2015 and 2016. The percentage of children aged 6–23 months with nonpolio acute flaccid paralysis (NPAFP) who received 3 doses of OPV through routine immunization programs is used as a proxy indicator for OPV3 coverage nationally and was 65% in 2015 and 67% in 2016. However, there was wide regional variation, ranging from 100% in the Central provinces to 28% in the Southern province of Helmand. The proportion of children aged 6–23 months with NPAFP who had never received OPV through routine immunization or supplementary immunization activities (SIAs) (i.e., “zero–dose” children) was approximately 1% nationally in 2016, virtually unchanged from 2015. The highest percentages of zero–dose children were reported from four provinces in 2016: Paktika (17%), Badghis (7%), Helmand (6%), and Nangarhar (2%).

During January 2016–May 2017, SIAs targeted children aged <5 years for receipt of one or both of the following vaccines: bivalent OPV (types 1 and 3) or trivalent OPV (types 1, 2, and 3 [until the global withdrawal of all type 2–containing OPVs, including tOPV, on May 1, 2016]). In addition, inactivated polio vaccine (IPV) was administered during SIAs to children aged 4–59 months who had not received IPV during a previous campaign and who lived in the 47 districts designated to be at very high risk for poliovirus transmission or in areas that had been inaccessible for three or more previous SIAs. During this period, 15 SIAs were conducted using OPV with or without IPV, including six national immunization days (NIDs) and nine subnational immunization days (sNIDs). Five case–response vaccination campaigns (i.e., mop–up campaigns) and five short–interval additional dose rounds (SIADs) were also held.

To accomplish eradication, it is essential that the polio program in Afghanistan continue to refine its strategies for vaccinating remaining pockets of missed children and reaching the high–risk mobile population. The polio program will benefit from completing its commitment to dedicate staff members’ time to supporting routine immunization without compromising core polio–eradication activities. Detection of orphan viruses, which are >1% divergent from the most closely related isolate, indicating extended undetected circulation of poliovirus, along with continued close genetic linkages with Pakistan viruses, highlight the need for Afghanistan and Pakistan to continue to prioritize coordination to improve surveillance, and to track and vaccinate their mobile populations, thereby stopping the ongoing cross–border transmission and reducing the risk for poliovirus circulation in hard–to–reach areas of Afghanistan.