2014–2016 polio resurgence

2014–2016 polio resurgence
Name	2014–2016 polio resurgence
Disease	Poliomyelitis
Virus	Poliovirus
First reported	2014
Location	Pakistan, Afghanistan, Nigeria, Somalia, Syria, Iraq, Cameroon, Ethiopia, Kenya, Niger, Chad
Dates	2014–2016

2014–2016 polio resurgence The 2014–2016 polio resurgence was a multi-country increase in poliomyelitis cases linked to wild poliovirus and vaccine-derived poliovirus that challenged global eradication efforts. The events mobilized international organizations, national ministries, and non-governmental actors across South Asia, Africa, and the Middle East and reconfigured priorities for the World Health Organization, Gavi, the Vaccine Alliance, Bill & Melinda Gates Foundation, United Nations Children's Fund, and national public health agencies. High-profile responses involved collaborations with the Global Polio Eradication Initiative, Centers for Disease Control and Prevention, Médecins Sans Frontières, and regional bodies such as the African Union.

Background

Poliovirus surveillance and eradication campaigns had reduced endemic transmission from Albert Sabin and Jonas Salk vaccine introductions through coordinated efforts by the Global Polio Eradication Initiative, World Health Organization, Rotary International, UNICEF, and CDC. Before 2014, endemic transmission persisted primarily in Pakistan, Afghanistan, and Nigeria, while previous outbreaks had occurred in Syria, Chad, and Somalia. Preceding initiatives included the Expanded Programme on Immunization, emergency action plans by the WHO Regional Office for the Eastern Mediterranean, and strategic plans endorsed at gatherings such as the World Health Assembly and donor pledges from the Gates Foundation and Gavi, the Vaccine Alliance.

Outbreaks and geographic distribution

From 2014 through 2016, confirmed cases and environmental detections were reported in multiple countries and regions. In Pakistan and Afghanistan, transmission in Khyber Pakhtunkhwa, FATA, Balochistan, and Helmand Province was documented, while Nigeria experienced resurgent detections in Borno State and surrounding areas. Conflict-affected states reported outbreaks: Syria and Iraq recorded re-emergence linked to population displacement from Aleppo and Mosul, and Somalia and Kenya reported cases associated with movements around Mogadishu and the Dadaab camps. Environmental surveillance found poliovirus in sewage in cities such as Karachi, Lahore, Islamabad, Kabul, Maiduguri, and Nairobi. Cross-border circulation involved transit corridors between Chad, Cameroon, Niger, and Nigeria, and between Turkey, Syria, and Lebanon due to refugee flows from Syrian Civil War zones.

Epidemiology and virology

Molecular epidemiology traced outbreaks to both wild poliovirus type 1 lineages and circulating vaccine-derived poliovirus (cVDPV) strains, with phylogenetic links to isolates catalogued in databases maintained by the WHO Polio Reference Laboratories and research groups at institutions like the Pasteur Institute and Centers for Disease Control and Prevention. Genomic sequencing connected chains of transmission to specific genotypes that circulated in Sindh, Baluchistan, Khyber Pakhtunkhwa, and portions of Borno. Age distribution skewed toward children under five in settings with low coverage documented by surveys from Demographic and Health Surveys and reports by the United Nations High Commissioner for Refugees. Case surveillance definitions followed protocols from the Global Polio Laboratory Network and case investigations involved collaboration with Johns Hopkins Bloomberg School of Public Health and the London School of Hygiene & Tropical Medicine.

Public health response and vaccination campaigns

Responses combined mass immunization campaigns, targeted mop-up rounds, and enhanced surveillance led by the Global Polio Eradication Initiative, WHO, UNICEF, and national ministries of health in Islamabad, Islamabad Capital Territory, Islamabad, Abuja, Addis Ababa, and Geneva. Campaigns deployed oral polio vaccine (OPV) and switched strategies toward inactivated poliovirus vaccine (IPV) introductions supported by Gavi, the Vaccine Alliance and procurement through the UNICEF Supply Division. Emergency operations centers coordinated logistics with partners such as Médecins Sans Frontières, Save the Children, Bill & Melinda Gates Foundation, and military or police escorts in insecure districts. Cross-border vaccination posts at checkpoints near Nad Ali District, Waziristan, Lake Chad Basin, and refugee reception centers used guidelines from the International Health Regulations and bilateral health agreements mediated during meetings with the African Union and European Commission.

Impact and consequences

The resurgence delayed anticipated certification of global eradication by the World Health Assembly and required reallocation of funds from other health priorities managed by organizations such as UNICEF, Gavi, the Vaccine Alliance, and the Gates Foundation. Economic analyses by teams from the World Bank and Harvard School of Public Health estimated increased costs associated with intensified campaigns, while humanitarian agencies like International Rescue Committee and Norwegian Refugee Council integrated vaccination into broader United Nations humanitarian responses. Political consequences included diplomatic engagement among Pakistan, Afghanistan, and Nigeria with partners including the United States Agency for International Development and bilateral health missions from United Kingdom and Germany.

Causes and contributing factors

Multiple drivers contributed: low immunization coverage in districts affected by insurgency in FATA and Borno State; access barriers tied to operations by Tehrik-i-Taliban Pakistan and Boko Haram; population displacement from Syrian Civil War and conflicts in Iraq; vaccine hesitancy amplified by misinformation spread through media outlets in Punjab, Sindh, Kabul, and Borno; gaps in routine immunization infrastructure in provinces administered from Islamabad, Abuja, and Mogadishu; and logistical constraints revealed in assessments by the World Health Organization, CDC, and evaluators from Rand Corporation. The mix of wild-type transmission and cVDPV emergence reflected interplay between OPV use, low immunity, and surveillance blind spots identified by laboratories in the Global Polio Laboratory Network.

Category:Polio outbreaks Category:Public health emergencies of international concern