Polio in Afghanistan, January 2019–July 2020

This page describes a CDC report on polio eradication efforts through July 2020.

Wild poliovirus type 1 (WPV1) was still circulating in only two countries: Afghanistan and Pakistan. After falling during 2013–2016, WPV1 cases in Afghanistan rose every year from 2017 to 2020. This report reviews the country's eradication efforts from January 2019 to July 2020.

What went wrong

• Bans on house-to-house vaccination. Since April 2018, insurgent groups have banned door-to-door campaigns in areas they control. From September 2019, vaccination there was allowed only at health facilities or insurgent-approved fixed posts.
• COVID-19. All vaccination campaigns were paused in 2020 because of the pandemic.

Cases

Of the 70 WPV1 cases from January 2019 to July 2020, 54 were in children under 36 months. Nineteen had never received oral polio vaccine (OPV), 15 had had 1 or 2 doses, and 36 had had 3 or more; 46 had never received OPV through routine immunization but had received at least one campaign dose.

A new outbreak. From January to July 2020, there were also 69 cases of circulating vaccine-derived poliovirus type 2 (cVDPV2) and one ambiguous vaccine-derived case, in 34 districts of 10 provinces, 57 of them in children under 36 months. Sixty-eight were genetically linked to an emergence first detected in Gilgit-Baltistan, Pakistan; one was a new Afghan emergence first found in Nangarhar province, and one had no link to known polioviruses.

WPV1 and VDPV2 cases by province, January 2019–July 2020. CDC figure.

Genetics showed repeated cross-border spread between Afghanistan and Pakistan in 2018–2020, with sustained local transmission in both. Thirteen "orphan" viruses — too genetically distant from their closest known relatives — signaled gaps in surveillance.

WPV1 and VDPV2 cases, January 2016–July 2020. CDC figure.

Vaccination

• Routine coverage: WHO and UNICEF estimated that 73% of infants received a third dose of bivalent OPV in 2018 and 2019, and 66% one dose of inactivated polio vaccine (IPV) in 2019.
• Never vaccinated: among children with non-polio acute flaccid paralysis, 1% nationally had never received OPV in 2019, but 25% in Uruzgan, 9% in Kandahar and 7% in Kunar.
• Campaigns: where allowed, there were 5 national and 5 subnational immunization days, two WPV1 response campaigns and one cVDPV2 response campaign. National days targeted 9,999,227 children under 5, and IPV reached 554,211 children (87% of the target) in the highest-risk districts.
• Inaccessible children: 449,756 (4%) in March 2019, rising to 2,844,197 (28%) in November 2019 and 2,655,821 (27%) in January 2020. In the July 2020 cVDPV2 response in the east, 107,768 of 1,101,740 targeted children (10%) could not be reached.
• Quality: districts failing campaign quality surveys ranged from 15% (November 2019) to 40% (July 2020).
• On the move: 24,009,626 doses were given at transit points and 1,296,109 at border crossings with Iran and Pakistan; from March 2019, everyone entering from Pakistan needed a yearly documented dose, adding 551,837 doses for people over 10.

Surveillance

The acute flaccid paralysis network — 2,501 health facilities and 38,140 community volunteers — exceeded quality targets in 2019, with 18 non-polio cases per 100,000 children under 15 and adequate stool specimens in 94% of cases. Sewage sampling at 23 sites in 11 provinces found WPV1 in 23% of samples in 2019 and 10% in 2020 (to August 29); in 2020, 23% of samples also held cVDPV2.

What needs to happen

On August 25, 2020, WHO's African Region was certified free of wild polio, leaving only the Eastern Mediterranean Region — Afghanistan and Pakistan — with endemic WPV1. The main obstacle in Afghanistan is the number of children who can't be reached in insurgent-held areas. The report called for:

• renewed dialogue with insurgency leaders, through nongovernmental and international organizations and new partners, to restore house-to-house campaigns;
• meanwhile, stronger alternatives for vaccinating children;
• integrating polio vaccination with broader health and humanitarian services — work under way before COVID-19 interrupted it — and offering several vaccines alongside other high-priority services to build demand.

Sources

• Martinez M, Akbar IE, Wadood MZ, Shukla H, Jorba J, Ehrhardt D. "Progress Toward Poliomyelitis Eradication — Afghanistan, January 2019–July 2020." Morbidity and Mortality Weekly Report 69(40), Centers for Disease Control and Prevention.
• The report describes the 2020 COVID-19 pause in vaccination campaigns as lasting 5 months in some places and as running March–June in another; this page gives neither length.