Progress Toward Polio Eradication - Worldwide, January 2018-March 2020

Area of Science:

• Public Health
• Infectious Diseases
• Epidemiology

Background:

• The Global Polio Eradication Initiative (GPEI) has successfully eradicated two of three wild poliovirus (WPV) serotypes.
• Wild poliovirus type 1 (WPV1) transmission persists exclusively in Afghanistan and Pakistan.
• Circulating vaccine-derived poliovirus (cVDPV) emerges from oral poliovirus vaccine (OPV) strains in underimmunized populations.

Purpose of the Study:

• To summarize global polio eradication progress from January 1, 2018, to March 31, 2020.
• To update on the status of WPV1 and circulating vaccine-derived poliovirus type 2 (cVDPV2) transmission.
• To highlight challenges posed by the COVID-19 pandemic to ongoing eradication efforts.

Main Methods:

• Data compilation and analysis of reported WPV1 and cVDPV2 cases.
• Review of progress reports from the Global Polio Eradication Initiative.
• Assessment of the impact of COVID-19 on immunization and surveillance activities.

Main Results:

• WPV1 cases in Afghanistan and Pakistan reached a five-year high in 2019 (176 cases).
• The first quarter of 2020 saw a fourfold increase in WPV1 cases compared to the same period in 2019 (54 vs. 12 cases).
• From January 2018 to March 2020, 547 cVDPV2 cases were reported across 21 countries, with increased outbreaks following the withdrawal of OPV2.

Conclusions:

• Polio eradication remains challenged by persistent WPV1 transmission and rising cVDPV2 outbreaks.
• The COVID-19 pandemic has severely disrupted critical immunization activities and surveillance, jeopardizing progress.
• Resumption of polio eradication activities will require significant enhanced support post-COVID-19 emergency.